Hi Andy,
Welcome to IIS!
How mechanically competent are you? The HEQ5 is not a complex beast and can be stripped down and rebuilt by anyone with a modicum of ability and common sense.
There are plenty of resources out there detailing how to service an HEW5.
First place I'd look is the astro-baby 'How-To' page here:
https://www.astro-baby.com/astrobaby...-sirius-mount/
Followed by any one of a number of YouTube videos by AstroBloke, Frosth Astrophotography and others.
https://www.youtube.com/watch?v=5RcTuPWCHug
https://www.youtube.com/watch?v=x79akiJO3pU
https://www.youtube.com/watch?v=lwZnLkzNQlw
https://www.youtube.com/watch?v=0yzFTjlpZaI
Cheers,
V.