Well It wasn’t yesterday had to divert and use an ILS. Which sort of defeated the purpose of going to the local airfield in Class G in the first place.
For training I don’t care what the approach minima is. I just want to be able to fly an instrument approach however the one every hour and max 6 a day make them more or less unusable.
Have these approaches been designed to fail?
Are you referring to Sywell EGBK and the 6 per day limit?
The plate for EGBK is not even published!
There are certainly plenty of GPS approaches with the DH so high that one can fly a VFR circuit at the same height – EGKA20 being one 
Six a day is .. weird! :) Leeds East allows for more of those in “practice” mode, if you comply with training requirements.
500 ft – I think that is the CAA’s default MDH for a non-instrument runway (see also EGMC, EGHC etc).
Their justification is that if you do an obstacle survey (and do it regularly), and install PAPIs+r/w paintjob, then you could go for real OCH, instead of 500ft+.
How expensive is that? Not sure, last I heard 100K+.
Is that ridiculous? Yep! “You’ve asked for it!” (c) CAA
You can do it for less – reportedly 30k per runway end – but I can well imagine an airport will ask itself "how much more traffic i.e. fuel sales, landing fees and stodge sales will we get to recover the money.
And since in Class G you can do what you like, the answer will probably be “not enough by a long way”. Unless you are Cambridge which watches inbounds on FR24 and if it looks like somebody is flying the IAP, they get kicked off the airport … reportedly!
On top of the 30k or 2×30k is the consultancy fee, paid to some ex CAA old boy in exactly the same way I paid a few k to a planning consultant who used to be the head of the Mid Sussex planning department 
I don’t get the subject header, given that nobody has posted the plate for, presumably, Sywell…
Sywell hasn’t had an RNP approach since c. 2020 – I think they lost it during the Covid lockdowns, for some reason.
As far as I know every single RNP approach that has been approved with either A/G or AFIS seems to have a DH of 500 feet. I’m not aware of any being lower.
Why would an RNP approach to 500’ DH/MDA not be useful? Same for an ILS to 500’? Both are IFR approaches just like any others and get you to a spot where a normal landing is possible, weather permitting, and doesn’t necessarily imply circling.
There are lot’s of airfields with them. Examples: LSZR, LSGC, LSZB, LSZG. Normally the higher than usual minimum is a result of the runway environment not qualifying it as an instrument runway even though the airfield is officially IFR with LPV and/or ILS approaches and even sometimes commercial air traffic. Could be geography, runway width, marking, lighting, etc.
Blois LFOQ has RNP LPV approaches to 250’ DH without ATC.
In the UK, IFR pilots are much more inclined to find “their own way” below clouds at 500 feet. Particularly at coastal airfields.
In Europe, where in some places this is considered as not legal, and where there is generally more terrain to deal with, pilots are much less inclined to do so.
I tend to agree these approaches are useful, simply because it renders the arrival more orderly. Unfortunately, the pace at which small airfields gain instrument procedures is very slow. In Germany, not a single airfield has started IFR procedures in 2023. Hassfurt (EDQT), which used to have instrument procedures, has lost them. We are waiting for Speyer (EDRY) to come in 2024.
