Once you accept Big Sky Separation works just as well as ATC for typical OCAS flights you will find the UK system actually seems to work pretty well.
MM
I dont know whether you remember the long thread sparked by my near miss with a glider in IMC in a twin? It passed so close I saw it in the clouds
The fact is we all think that IMC OCAS is the world of small light GA. That airpace is also inhabited by commercial aircraft right up to A320 s and 737s.
All will be fine until the day the unthinkable happens then all change
I would certainly make it obligatory to have a transponder with altitude reporting to be legally allowed to cloud fly
Pace