Hi, thanks for all your comments and encouragment.
I have been reading up and looking up!!!
Also built myself a battery box for powering my gear..... Once it arrives.
I could have bought a decent power supply for a similar price to my DIY unit but I wanted my own spec....
Lithium iron phosphate, 17ah, isolator switch, 4x USB sockets, 2x 12v sockets, individual fused and switched feeds, and red light in lid.
Some of the commercial unit seem to have unesessary gaskets that I don't need..... Radios, inverter, torches etc. I just wanted max amphours.