Broken flex? Used to have to shorten flexes quite regularly as the cable
breaks within the insulation, often where the flex enters the drill housing.
Instead of moving the drill around, try moving the flex while the drill is
switched on.
If it is the flex, it ought to be straightforward to remove all the screws
holding the two halves of the drill together, remove the flex, shorten or
replace and reassemble.

Yes - got in one. Thanks!

I had originally jiggled the flex about when I noticed the problem,
but I obviously wasn't doing it hard enough. I got side-tracked by the
consistency of the effects of tilting the drill as I described.

Anyway, now fixed and as good as new.

Thanks,

Ian.