I think the TGV is a pretty cool engineering feat, testament to the commitment of the French Govt, the french public and the engineering / train companies. I think the various High Speed Lines have taken around 4-5 years to build.
GIven that we are physically a smaller country than France, with a correspondingly denser population abutting certain areas of the route, consultation is inevitably going to be a complicated and time consuming process. Despite my own enthusiasm for such projects, questions do have to be asked about the national economic benefit - I haven't really seen a particularly compelling economic case for building such lines, and they will cost billions and inconvenience many with compulsory purchase orders etc.
We should not do anything to dilute the democratic process - Government has far too much power as it is - there should be no question of beefing up compulsory purchase laws etc. Make the economic case, demonstrate the national benefits, and get the public onside.