You're next problem is to get fully comprehensive cover from your UK insurance company for more than 3 months abroad and European breakdown cover, again for more than 3 months abroad. Search on this forum, there are 1 or 2 Swiss companies that insure UK registered cars. You can sort that out when you're here I guess.
When driving in most European countries like Switzerland, you should carry your car identification papers (i.e. in your case, the D5 'log book') and your driving licence; they don't have the '7-day-producer' like they do in the UK (in Switzerland they will just fine you!). I would also request the 'green card' from your insurance company; an internationally recognised insurance certificate. Although it's not a must in most of Europe: http://www.direct.gov.uk/en/motoring...ance/dg_067624
Other things you should have include a first aid kit, warning triangle, maybe a yellow vest, GB sticker (or 'Euro' plates), and headlight beam deflectors.