Apart from the 40 hours or so to get the rating some of the currency requirements are:
That's where the UK-only IR(R) comes in - minimum of 15 hours training (OK, it took me twice that, but I started and stopped several times over about three years), test with an examiner every second year, no other currency requirements (apart from common sense).
With this rating UK hobby pilots can fly in cloud and can fly approaches. The main limitation is that we're still not allowed in class A, so no airways.