Your boiler heater element may have shorted out.
That is known to trip the RCD on a Francis Francis x1, and other models have the same boiler.
Thanks, I think you were right but it was happening due to moisture in the electrics (the seller hadn't drained the machine that well so the box was a bit damp). It's now been dried out and is working perfectly.
Thanks, I think you were right but it was happening due to moisture in the electrics (the seller hadn't drained the machine that well so the box was a bit damp). It's now been dried out and is working perfectly.