New light fitting coming on with wrong switches
The solution was that the wires were connected correctly but somehow the switch had stopped working during me changing the light fitting, I tested all the wires and the switched wires were showing continuity constantly despite the switch being off.
I tried the switch itself directly with no wires to check it was definitely the switch and it was, switch replaced and all worked fine.
When I first started I thought it seems like the switch wasn't working but I ruled that out in my head as it worked fine with the old  light so not exactly sure what the reason for it failing was or just coincidence, but it was a cheap fix in the end.