Hi Iain,
For covers, you might want to contact C&J Marine - their website is at
http://www.cjmarine.co.uk/ . We have have a main sail cover, pop-top and cockpit wind deflectors all made by these folk. They were on the boat when we bought it, so I have no experience of dealing with them. I have also seen that you can order the pop top, wind deflectors, main cover and sails through the online store on this site. I'm personally inclined to order replacements for ours from here - particularly as the Doyle sails can be ordered up very easily.
Trailer-wise, I think you may need to see about having one specifically fitted up for the boat. It uses a contoured bunk arrangement to provide support for the hull and a central bunk for the keel. The trailer we have came with the boat, and it carries a Hunter Marine manufacturers plate on it - it's not a standard Snipe or Indespension item.
What did you do to fix your depth sounder? Ours is a bit spotty too, but so far I have been minded to just whip it out and put a new one in.
As far as the big table goes - I love it. The size of it was one of the things that most impressed me when we first looked at the boat.
Regards,
FW