@Jacobm001 do I look crazy to you ;) but no, in University they thought doing C and C++ is really enough for physics - though of course real physics is done in FORTH ;)
@Jacobm001 Well the little electric motor inside does not spin around any more - one of the four screws went right into it and you can see a hole bored (thorough the permanent field magnet) into the copper wire (that was the armature).
Also the other screws went into a PWB and cut at least one sub-millimetre wide track. Just this instant took a telephone call from the Installation Company advising me that the replacement will be available to be fitted on Thursday - so things are looking up! 8-)
@SlySven The Op has since stated that they haven't mortally wounded any RPis after all - the fuses did seem to protect them. Sounds like a close shave though... 8-)