I think your being optimistic. I am hearing stories of upwards of 200K being spent on getting GNSS approach approval and it’s still not approved after some 6 years.
Well i can't understand how it should come to £200,000. There is no physical infrastructure to provide. All costs are in the fees: aerodrome survey, stakeholder consultation, approach design fees and of course the CAA approval charges. The CAA are being very difficult and obstructive which itself adds to the cost. They are demanding, for instance, that ATC are in place for all procedures, and do not accept trained A/G, although the regulations do not require it. This will inflate the cost a lot where ATC do not already exist and may have been included in the hearsay. My estimate may well be out of date but it was an estimated cost a few years ago when I had some direct involvement in the process.
EASA are very keen that small aerodromes have a GNSS procedures at low cost and the regulations do not require ATC. It is a poor reflection on the UK that there are so few GNSS procedures in place at small aerodromes. PPL/IR have done a lot of work in supporting and promoting them but continue to hit a brick wall. Meanwhile individuals are designing their own procedures which soon become widespread amongst locals at a particular aerodrome and flown regularly.