Wow, thanks so much for all the help and support, I'm feeling a lot less intimidated and a lot more excited by the purchase now!

Tulip - Thanks for the pointer on the saddle and the pedals. I'll definitely keep it in mind

Bluetree - You make a really good point. The ride is being organised by one of my local bike shops, so I think I'll go and try to get some more info with them about what exactly we'll have to use out there.

I'm not sure about the 52cm - they took my measurements and said that's what would be the right size for me - but I haven't been able to go out on any test rides yet because the roads are covered with snow and ice at the moment. It's very uncharacteristic though and hopefully will clear in the next few days - I'm getting so impatient!!

Kiwi Stoker - Wow, thanks for the local knowledge, I'm sure it will prove absolutely invaluable I'll definitely be sure to mention the points about the roads and the tyres to the organisers. I'm so excited to be getting down to New Zealand, everyone I know who's been just raves about it.

Muireann - Thanks so much for all the links - I had a rough idea of the key terms from talking to some cycle-keen friends, but the links really clarified things in my head, and the female-specific information was much appreciated! Sheldon Brown is some resource - seems to be a one-man encyclopedia, but lots of great articles

Once again, thank you all so much for taking the time to reply, and the consideration you've given to your responses, I feel like I'm in a much better position to ask for what I want now!