Thanks for all the input. Referring to the manual it details 35Ah upwards, wonder why that is? think I'll fit a car stereo, amp and some speakers as well,ha.
I'm intending on housing the battery and associated electrical doodahs in a large tool box. I will also be able to store my pump and other marine item in it.
My mate gave me this, it's got a 12v socket, volt meter and USB sockets. There's a lip on tool box so I'll install it just below to help prevent water ingress, although it's meant to be waterproof. I'd have a switch with fuse between battery and the trio.
If I pull the handle up on the toolbox it'd be like an A frame on my wee SIB
Sure I've got a 4 gang cig lighter adaptor somewhere, I could fit that internally if the weather didn't suit external charging.