I believe you are from CS ;-) like me, CZ is just last 18 years....
Yes, LKPR 1957-1959, LKPM 1959-1969
Your MEP is the best bet. EASA couldn't care less what you write in their comment website. You could write that you are about to blow up the Earth; their response would be that this will be OK after the EU-US Bilateral Treaty on Earth Destruction is signed. And they will drag out the used Trabant salesman Mr Seebohm saying that the treaty is imminent.
It's obvious from the Transport Committee videos that the assholes in charge of EASA fear the Euro MEPs most of all. They like any form of democracy as much as Count Dracula liked sunlight.
IO, could one not "design" ones own GPS approach for an airport? I mean, all one needs to do is go there in fair weather, establish parameters for a descent without bumping into stuff and then sell it/give it other pilots? Be your own little one man Jeppesen?
Yes of course. You would not be able to load it into the GPS database as a "proper" GPS approach but you could save it as a flight plan comsisting of a set of user waypoints, etc. A number of these already exist. You have to
manually switch the GPS lateral deviation sensitivity to 1nm FS and then 0.3nm FS. But apart from that it is avionics-functionally equivalent to a published GPS approach. You should design it with a topo chart and test fly it in VMC, obviously. Choose a generous MDH e.g. 800ft.
Sure, it would be illegal to fly it, but how exactly would they know that you did fly it without sitting next to you?
It is 100% legal to fly a DIY approach, GPS or conventional-navaid, in a G-reg, in any airspace which does not prohibit this (and the UK doesn't prohibit it).
It is probably not legal to do it in an N-reg (FAR 91.175), even outside the USA.
Lots of DIY approaches are flown into airports which don't have ATC, UK and abroad. In many cases it is really easy to do it perfectly safely e.g. if the airport is on the coast. With ATC present, it is a little more tricky, but nearly all airports with ATC also have a published IAP so you just fly that.