The saga that is the National Broadband Plan (NBP) has had more twists and turns than a John Grisham novel.

But finally, it seems, the process may be inching towards a conclusion, with a positive ending in sight, although not guaranteed.

The submission by the National Broadband Ireland consortium of its final tender today is a significant milestone, and one that some doubted might ever be reached.

The withdrawal of shortlisted bidders SIRO and then eir from the competition appeared to signal the death knell for a process that has appeared increasingly interminable.

Questions were correctly raised about how the Government could possibly expect to get value for money when the last remaining bidder effectively had it over a barrel on price, terms and conditions.

But still the process rolled on, with Minister for Communications Denis Naughten satisfied that his department could extract the best possible deal from the sole remaining bidder.

Then doubts emerged about the future of the enet-led consortium itself, when RTÉ News revealed in July that SSE had pulled out of the group, taking with it its financial muscle and infrastructure experience.

enet rapidly replaced SSE though, bringing in the State-backed Irish Infrastructure Fund, which had bought a 78% stake in enet a year earlier.

Fast forward then to today.

A tender has been received and the project team in the Department of Communications will spend the coming weeks scrutinising it to decide whether it can declare the consortium the "preferred bidder".

Despite today’s undeniable progress there remains, however, many unknowns, concerns and a chance it could all still unravel.

First, there is the issue of the ever changing nature of the National Broadband Ireland consortium.

After the upheaval last July caused by SSE’s departure, the assumption was that project lead enet had finally got its house in order.

But today it emerged that there has been further significant change to the membership of the consortium.

Out has gone John Laing Group plc, an international infrastructure development group with massive experience in large project rollouts.

The Irish Infrastructure Fund, it appears, has taken more of a back seat and is now only involved through its shareholding in enet, not in its own right.

While enet, the leader of the pack through the whole process, has suddenly morphed into a "partner" alongside well established telecom infrastructure providers Nokia, Actavo, The Kelly Group and KN Group, who have entered the fray for the first time.

The reason for enet’s backward step has not been made clear, with the consortium refusing to comment.

Instead the project is being driven by Granahan McCourt, a private investment firm that claims to have three decades of experience of partnering with governments and businesses to drive technological change, including the design, construction and deployment of large-scale telecoms infrastructure.

But the significant changes are strange given the modifications to the structure only two months ago, and the chopping and changing won’t inspire confidence in some quarters.

Another unknown is how much the NBP will cost us, the taxpayers.

There have been big numbers tossed around for many years, tipping €1bn at the upper end of estimates, with the State predicted by some to be picking up the tab for up to half of that.

But due to the secrecy around the tendering process, the actual bill still isn’t clear.

All we know is that the Government has allocated €275 million in the 2015 capital plan to cover the first five years of the project.

How long the delivery process will take, should the consortium get the go-ahead, is also still unclear.

Reluctant to give a hostage to fortune, successive ministers have shied away from giving a deadline and that’s just as well because the timeline has progressively shifted back with delay after delay.

Clearly the rollout will take many years, with the final premises unlikely to be connected to high-speed broadband until the early to mid-2020s.

We still don’t know for sure the technology that will be used either.

The plan promises a minimum download speed of 30Mbps and the department’s team has consistently referred to that being predominantly provided over fibre optic cable that will go right into people’s homes and businesses.

But when push comes to shove, it might be that a less future-proofed option will have to be deployed in order to connect the really hard to reach locations.

Finally, the big elephant in the room is eir.

Prior to its withdrawal from the NBP process, eir signed a contract with the Government that committed it to delivering high-speed broadband to 330,000 premises in rural Ireland.

This action reduced the intervention area for the State, in theory lowering the cost of the plan to the Exchequer.

But that move was also perceived by many as eir cherry-picking the easiest to reach premises from the plan area, making it harder for the eventual winner of the NBP contracts to get to the remaining homes and businesses without having to use eir ducts, poles and other infrastructure.

Communications regulator Comreg is looking in detail at issues around the prices charged by eir to other operators to access that network.

But in the meantime if eir wants to it has the capacity to slow down and frustrate the rollout through pricing and access, although it should be said that eir has been consistent in saying that it is and will continue to work with the consortium to ensure the NBP progresses.

A statement from National Broadband Ireland also referred to the company having long-term access to open eir’s rural pole infrastructure, as well as its duct network.

Of course, all this corporate wheeling and dealing means little to the average broadband user in rural (and often not so rural) parts of the country.

They just want to see affordable, reliable high-speed broadband delivered as soon as possible, no matter what it takes or whose name is on the van that brings it.

Today’s developments bring that reality a decent step closer to ordinary users.

But based on past experience, they could well be forgiven for treating it all with a healthy dose of scepticism.

Comments welcome via Twitter to @willgoodbody