bonj said:
1) presumably it's not too difficult to fit them onto existing mechs/brake calipers - any 'gotchas' to watch out for?
One main one: if you have V brakes, you'll have to be careful what levers you buy. In general, V brakes and levers for drop bars don't mix. There are exceptions but they're not mainstream, available-in-every-branch-of-
Halfords levers. If you have cantis or dual pivots, no problem. I have no idea about disc brakes.
2) do either of the brake cable / shifter cable get routed inside the handlebars once they come out of the shifter thing, if so at what point do they come back out. (excuse my ignorance, i've not spent much time looking closely at drop bar bikes)
Shimano STI levers are designed to route the brake cable along a groove in the bars, and the gear cable grows straight out of the inner face of the lever - near where your thumb would rest if you were on the hoods. Campag levers have both cables run along the bars (and in my opinion are much prettier - and don't cause a problem if you want to use a handlebar bag). If your 'bars don't have a groove or grooves, don't worry: the cables will form a slight bump beneath the tape, but if you fit them along the front edge of the 'bars it doesn't matter much.
If you go for Campag levers, you must either have Campag elsewhere, or you'd better consult
Chris Juden for what bits work with what other bits. (I have a hybrid "Shimergo" system that works very well thanks to this priceless gem of information).
Shimano or Campag, the cables emerge where the tape ends near the stem.
When you come to put it all together, use good quality insulating tape to hold the cables in place, while you fit them and the levers. THEN wrap the handlebar tape. You'll get in a tangle trying to make the 'bar tape hold the cables and go where you want it to.
3) presumably the hood lifts up from the bit where the whole caboodle is clamped on in order to wrap the bar tape under it?
Yep.
annoyingly it's going to be probably at least £150 to do it, for which i could gt a new bike - but probably not as good. I still don't think i would want to get a new bike 'cos if I did i'd probably want to be spending 6 or 7 hundred quid.
If you're careful, do your homework, and are prepared to wait for the right parts to come up on
EBay at the right price, you should be able to do it for quite a bit less than that.