Well, so disappointingly the repairers were faffing about so I kicked up a fuss on twitter and John Lewis have refunded me.
The KS8000 was ideal and having only paid £1,470 for the 65" one, I'm struggling to find an equivalent for similar money.
I've ordered a OLED65B7V for £2,249 from Currys but they are currently awaiting stock. In the meantime I'm still trying to get together a shortlist of potential replacements that may be better suited.
So far I'm considering:
OLED65B7V £2,249
OLED65C7V £2,249
SONY BRAVIA KD65XE9305 £1999
The lower spec Sony's XE90/85 look to be inferior to my old KS8000 and in the 90's case actually more expensive.
Anything else I should look at?