You've all been very helpful, much appreciated. I think I've made some progress via the above advice.

I managed to consolidate 5 inputs then send to where I wanted. But a problem I faced was that I originally wanted to consolidate more than 5 (15 or so) but every time I tried, the PSBT file wasn't read by the coldcard until I reduced it to 5 inputs. I've now also tried another consolidation to send more, and this time it didn't even read the 5 inputs but when I reduced it to 3, it's now worked.