[Fiddybux]

Hey thanks Northy. I strongly suspect the servo wasn't at fault on account that I gave it a good testing to try and get it to slip...but it didn't.

It is good to know that electrical noise can do this to a servo as well.

It would be a shame to bin the motor because it's a real belter, so I'll get it all cleaned up and give it some TLC as you suggest - fingers crossed it will fix the problem.

Cheers.