I have bought from Battery Megastore in Tewksbury. Four purchases to date and I have had good service. They also have an eBay shop but I tend to give them a phone call. https://www.batterymegastore.co.uk/
My experience with Tanya was poor, I checked voltage of two identical batteries upon receipt and found them at 12.4 Volt and low on water. They clearly did not maintain them in stock and expected me to fit and connect without checking. I sent them back and got a full refund and even that was not straight forward. My feedback to their website was rejected out of hand and if you go to their website you will see they have no negative feedback...and that's because they only publish the good ones.
I ordered the battery from Tanya at 7.00am yesterday morning. Got a call from them at 10.00am to say awaiting a delivery but that I would have my battery delivered next Wednesday, was that a problem - no says I.
Got a message this morning at 8.00am and battery delivered at 8.30am....
Spoke with them to make sure they would not duplicate the delivery and they said that their stack came in later yesterday afternoon and my battery was immediately dispatched
Tayna , get our vote.
We bought two leisure battery's that were delivered to an Aires in Portugal on 26/December/18.
They delivered a similar service to 3 other vans that we know this winter, and seem to have a very efficient system of delivery at a good price.
Hard to beat a positive recommendation from friends.