can't find any Mission 780SEs for sale at the moment but have set alerts in case any come up. I'll grab them as they seem to go for beer money. Last sales were a pair in Bristol and another pair in Paisley - each going for £65.
In the meantime will do some more digging on the other recommendations. The MartinLogan Motion speakers look very interesting but never heard them and don't fancy just taking a punt on new ones (seems to be only from Absolute Sounds here in the UK). There was someone who was trying to sell Motion 2s about a year ago starting at £250 and seemingly sold at £150.
Current: [P20] Roon/Tidal > Custom PC> Chevron Paradox NDF16 > Phast Pre > Neuro. 686 > Tannoy Berkley (RFC tweaks)