VW T4 Electric Hookup Recommendations

[vaguelyfamiliar]

Afternoon, I have a 2001 T4 Kombi that I'd like to add electric hookup to, anyone have any recommendations for someone in the Herts/Beds area?

I'm looking to add
External hookup
100AH (ish) battery
A couple of sockets, with USB
12v socket
A couple of 12v USB sockets
Split charge relay

Thanks