Hello Keith
If you happen to speak German, this is a useful page:
http://www.waffensammler-kuratorium.de/Dillenbajo%20M%2062/BajoM62ge.html" onclick="window.open(this.href);return false;
If not, I can tell you that inter alia it says the bayonet should be browned, not bright like the M1841 bayonet. I have an M1862 which took me a while to find a bayonet for, but they are out there and you shouldn't have to pay much over £200 for a good one. Ebay is the best bet. It may take a while tho and you need to have patience. Resist the temptation to buy something like this:
http://www.waffenhandelimspessart.de/index.php?option=com_articlelist&view=article&id=31" onclick="window.open(this.href);return false;
which has no original finish left. I got mine from this dealer, who is a bit hit and miss with his stock but seems reasonable enough on prices:
http://www.huesken.com/index_e.html" onclick="window.open(this.href);return false;
I would rate your chance of finding a sling at about nil. However one never knows what will turn up. I've also managed to buy an M1841 and bayonet; it was not cheap, but as you say, there's very little around in the UK. Are you a Franco-Prussian War collector or is your interest just in the firearms?
I will try and upload some photos in the next few days.
Good luck!
S.
PS welcome to the Forum!
PPS that bright bayonet in the first link is a French bayonet.
PPPS they come without scabbards - none were issued and the bayonet was carried fixed on campaign. Sounds incredibly inconvenient, but it's true.