Hi Weedman, there are several of us on the site who have upgraded or are upgrading Southampton and Richardson (same thing - different name and colour scheme!) tugs.
Look for NPJ's Southampton thread, or just use the site Search function to look for 'Southampton or Richardson. The secrets you are looking for are there😉👍 Cheers, Doug 😎

The Southampton has lots of screws around the deck but some are under the bollards so you need to remove them, there are two aft bollards which need to be gently prised loose but the others are scewed to the bulwarks.
I changed the radio in mine as well as the motor/gearboxes and fitted a v.tail mixer from www.mr-rcworld.co.uk with 2 speed contollers as well as converting the battery holder to take a six volt nimh pack. The effect is awesome.

Happy sailing😁