An alternator is about £100 for a new/recon or as little as £15 from ebay, say about £100 for fitting if you aren't confident of doing it yourself. The central locking on my 25 year old Fiat uno has never worked, nor does it really bother me. Drivers window, prise off the door card and have a poke around in there, won't be too difficult. Is it electric? Is there a connector loose? maybe fallen off a runner? basic checks, you never know.
For the clio again, it's up to about a ton for the motor and the same for fitting.
Thanks for the reply jaik. The central locking is only annoying because it works to unlock, so when I open the drivers door all the doors unlock, but wont lock again so I have to run around and lock every door individually. Wouldnt be as bad if it were 3 door.
Il have a look at the things you pointed out, thanks for the advice.