Mudguard "fettle" has worked a treat. 4 holes and 2 zip-ties later, no tyre rub.
The creaking bottom bracket that took a couple of B/B removals, greasings, tightenings, test-ridings..was..in fact.. my (not tight enough) seat pin clamp ! DOH!
Bike is getting quieter by the day.
Maybe I should just relocate to inner London.