My reverb feels a bit rough when it is compressed, as if something is rubbing inside. There is no noticeable additional play to it. It is two years old and has never been serviced, nor has it ever developed any faults before. Has anyone here had a similar experience or able to offer any advice?

Cheers and beers, Ambrose.

sell it on the classified for £125 and by a new one for £150 ish

It may just need a clean and regrease. I’ve had mine apart to replace the upper bushing and regrease it. The hardest thing is gripping the stanchion without damaging it. You may also want to do a seal/bushing service but be aware that, as with all things SRAM, parts are stupidly expensive. I’ve also had one serviced by Loco when it started losing air. That was about £100 IIRC.