Hi James,
Sorry this is a late reply as I have only just seen this post. You have probably got fully serviced winches by now. My 235 is a 2003 and I think some of the earlier boats had Antal winches like mine, both of which are two speed, model number Antal W16.2ST (2001 model). I posted about this here:
http://www.parkerseal.or....aspx?g=posts&t=1709
The early Antal winches do not come apart conveniently like the Lewmars (or later Antals: 2004 on!) with a circlip at the top. With my winches, the barrel comes off by removing the self-tailer (a coiled circlip and one screw, I think) and then four Allen head machine screws but this leaves you with no access to the ratchets and pawls - and no obvious way in. I had to remove the plate in the headlining inside the cabin (several tiny screws) to access the underside of the winch and then unbolt the complete winch base from the coach roof. Once off, you can access the screw in the bottom of the winch that holds it all together. I found an exploded diagram online which I can send you but I don't know if there is a PM facility on here.
Antal do a service kit and, as John Edwards suggests, you have to keep everything in a tray to make sure springs or pawls don't fly off into the long grass. It's a messy job!
Reassembly of the winch is straight forward, if fiddly, but you then have to seal the base back on to the coach roof properly. I set mine on a good base of CK1 sealant and bolted it down. It doesn't leak - and I haven't tried to get it back off again! Finally you reassemble the barrel and self tailer.
It would have been sensible to have a hole in the coach roof within the sealed area beneath the winch to access the screw in the base.
Hope this is helpful but - caveat - I am trying to remember the job in detail from two years ago...
Adrian Raymond
P235 no.15 "Gemily"