This is worth a try, even though it may not cure.
Remove the top cover from the printer completely.
Blow out all the muck that has accumalated over the years, with a hairdryer set to cold and maximum blast. Use a long thin brush to assist.
Do not do indoors, otherwise mum/wife/girlfriend might put you in hospital! :-)
If possible disconnect/connect printhead motor connections - it is not reversing.
As a matter of interest, where are you located? I am in Hammersmith, West London.
Good Luck - Keep us posted.