On Dunfermline leg you pass some COOPs open till 10pm around 60-70km into leg. St Ives leg there is an ESSO after Barkway at 60km when waiting to cross A505 Flint Cross. Go right onto pavement before crossing A505 to reach it, less than 50m. I plan to stop there to top up water.
Not sure this is of any use to you, as I'm not doing LEL, but in Scotland we have Top Up Taps. I often use the one in Montrose, and I always plot their location when I'm doing longer routes if I'm going near one. They're basically public water fountains, maintained by Scottish Water. They are cleaned and disinfected weekly.There's a map here: https://www.yourwateryourlife.co.uk/find-your-nearest-top-up-tap/Sam
Publicly accessible taps are marked on OSM and there are also a several of apps: https://www.water.org.uk/news-campaigns/campaigns/refill/