Thanks for all the help.
All wired up using flexi 16mm2 110AMP cable direct to solenoid. While I was fiddling I also finally got round to fitting a strip fuse on the main brown cable (as recommended!).
Although not properly connected, there appears to still be conectivity between the two posts on the ammeter so will leave 'as is' for the time being. If any problems,I'll piggy back both wires on the same post. I've capped off the old alternator wire but left it, in case I ever want to revert back.
