Skywatcher Skyliner 350P Base slewing issue.

[Simon128D]

Hello all, 
It will be coming up to 10 years since I got my 350P GOTO from FLO and has been the most amazing scope to use and will continue to use it for many more years to come but since about two years ago I've been having an issues with the mount base motor when slewing for anything from GOTO or just tracking an object. 

It seems the motor gearing is slipping a lot. In most cases the star alignment goes just fine but after a while an object will be gone from the eye piece and normally I just need to press and hold the right arrow but more and more I have to hold the button for 10 seconds or more to get any actual movement. I can speed this process up by increasing the slew speed to anything above 5. 
I have removed the black plastic housing to have a look at the internals and there does not seem to be any easy way to do maintenance on these mothers. I couldn't see any way at all to remove the motor from the base and from the angles I had available it appeared to be a sealed unit. 

Is there anyone or anywhere that would look at the base to service it for me? 
I suspect it will just be a matter of applying fresh grease or lubricant but I am not sure what is involved in doing this or what the risks are of causing damage. I can see one of the encoder wheels and I would dread to cause any damage to that. 

I have managed to get used to it in the sense that I know if I use GOTO or manually slew to an object to then use the hand controller so that when I press the right arrow button I get movement and finish centering with light presses of right and up arrow the tracking will usually be solid for long observations. 
I would like to get this back to really good working order though and I usually spend 15 minutes or more observing an object so the tracking of the GOTO is essential for me. 

 

Any help or advice from any of you will be greatly appreciated. 
Simon