Update
Amp got worse before i could get the spray, now only working from the headphone Jack. No output from the speaker.
Tried the Deoxit spray and no change. I did it 3 times as recommended (short burst, headphone jack in and out several times leave it 2 mins ) - no joy.
I've got a headphone jack on order, so will try that next.
@goingdownslow is this similar to the one you used? https://www.ebay.co.uk/itm/184174490058