hi Steve,
from what I can see, if you've got the goto base, the only thing you'd need to change on the OTA is the circular bracket on the side of the tube so it connects neatly with the altitude bracket on the goto base unit. Dunno if you can buy them separately, as the whole goto kits are pretty pricey.
The link below is from the Skywatcher site, and has a link to the "manual" which explains how to change this bracket over.
https://skywatcheraustralia.com.au/p...ts-for-goto-2/