IO540,
I generally find I agree with your approach to flying matters, but your last post on this thread does need some response.
1. The CAA is the sole authority on limitations on UK permit aircraft. Not only does the CAA have unfettered rights under the ANO to set such limitations as it thinks fit, but EASA specifically has no authority, at least at present, on Annex II aircraft, which include all home built aircraft.
2. The 1980 ECAC Protocol specifically enables home built aircraft of any signiture country free access to all others. Whilst politics being what it is, not all European countries signed it, and inevitably, it is being interpreted slightly differently where it has been signed, particularly in relation to microlights. Nevertheless, for Group A homebuilts, free coming and going without prior permission of UK aircraft is welcomed by Austria, Switzerland, Germany, Holland, France, Hungary, Ireland, Denmark, Sweden, Finland, France, Luxembourg, Malta - (just some examples). Some others, eg Norway, Spain, Portugal, require prenotification a couple of days before by fax of Permit and Insurance, response always having been positive.
Standing out is Belgium, that centre of EU cooperation, who almost alone require a fee, 80 Euro, to be proven to have been paid before they give permission. Nevertheless, there is no significant restriction on European flight in UK Group A homebuilts. There's a paper on this on the PFA web site.
Interesting that the C.I. preserve their independence by requiring prior permission, but state that this is given by their acceptance of the flight plan. No hassle at all, I go there often.
3. As you say, 90% of PPLs don't fly abroad. Why is it not highly desirable to give at least those a very valuable upgrade, for useability of their aircraft in UK weather?
4. Very few PPLs ever fly at oxygen FLs, and your comments on this are almost irrelevant to the overall benefit to the majority. However, the very flexibilty and performance of the best kit types would give exactly the same, or better, facility if IFR flight is allowed, than you have in your TB20. I have seen a 300hp kit plane under construction which is having an oxygen system and de-iced prop fitted, in expectation of eventual IFR approval. It will cruise at least 40Kts faster than yours. And don't forget that Glasair III with a 450shp turboprop which had a photo shown on another Pprune thread a few months ago!
All the best, Mike.