sudomod

Can anyone advise a good source for batterys in the UK?

Seconded.

I like https://www.coolcomponents.co.uk/ but for some reason the shipping on the battery is really high there.

Ive found this but im hoping for a bigger capacity...

http://uk.rs-online.com/web/p/lithium-r ... s/7916460/

Not sure whether it would be easier to buy a power bank and strip it apart. Would it be easy enough to wire one to the powerboost if i did this?