Thanks for the info,
The pump on the boiler is the old wilo,
It too has a 5 pin plug, with 5 wires,
It’s the eco plus 831 R1,
VUW gb316/3-5
GC 47-044-32,
According to wilo, both 3 & 5 wire pin plugs were fitted early on, the boiler is 2006, so one of the first I think,
Still in great...