I suspect I'm the superannuated IMC rating holder referred to above (with an FAA IR - that was at least twice as hard to get as the IMC).
I've found that flying round the UK in real IMC, the volume of traffic is usually low enough that you do get service from radar units. I can't recall ever being refused by Brize (or anyone else) when I needed them.
On a Sunday afternoon bimble in VMC, with lots of folks around, it's a very different story.
And yes, I have filed an IFR flight plan and flown it in IMC most of the way, including an ILS at the far end. I got told off rotten by the editor of a certain "official" publication for doing so - with the immortal words "The IMC is only a get-out-of-trouble rating". I told him that it doesn't say that on my IMC, and the ANO that I read said I'm entitled to fly IFR in IMC up to and including Class D.
There are two schools of thought on this one, and I doubt they will ever be reconciled. There's also a school of thought that says the FAA IR isn't a real IR. But you get that in every walk of life (even in my present career).