Only having been involved in classic car and bike engines I have never had the occasion to change a timing belt. My wife's Citreon C4 belt now needs replacing, is it a fairly straight forward job, will I need any special tools etc. I will probably buy a Haines manual first.

Should be fairly straight forward although tight. Put a new water pump in while you have it apart.

If its a 1.6 petrol its a straightforward cam belt change with reasonable access if its a 1.6hdi its not particularly difficult but access is faily restricted. With hdi don't forget to use lock thread on the crank pulley bolt