Thanks for this useful discussion.
It was Boscombe (North to South through the west stub, then the next day South to North, east of Middle Wallop - both times I was well outside the ATZ's.)
I wouldn't have carried on through the MATZ if I had been refused entry - could have gone round - but ATC didn't refuse, just gave no reply to my request. I did ask at the opening contact - "Boscombe Down - G-**** request FIS and MATZ transit..." then in my CARPACER I asked for MATZ transit again.
Just a bit surprised... as Opencirrus pointed out, they may have been busy on another Freq. Certainly I could see no traffic around the airfields.