Decided to do a shorter run this morning to try to ease the blister situation. Last week's was healing well and I'd been to the runnning shop on Saturday and bought 2 pairs of eye-wateringly expensive socks (husband shall never see the receipt...shh).
Went out this morning with no Compeed on it, just vaseline and a pair of twin skin socks. Ran 4k instead of 8k.
It worked! Usually I've been getting the first blister pain at 2k. Today I felt a small twinge at 2.5k then nothing more. On getting home, the area looked and felt the same as when I set off!
So thank you to all my friends here who suggested options - if I didn't try your suggestion today, I probably will in the next few weeks!
At least I feel back on track for my Race for Life on 15th July