I have been offered a full time job, but realise the morning commute is going to be more difficult than anticipated. I am not sure whether I should ask for a reduction in hours to allow for the journey before I accept the job. Also is it best to email the interviewer, so he can consider his response, or should I ring?
The best time to negotiate Ts and Cs is when you have the formal offer. It's not that unusual for people to get a job offer and put a case for improved salary, flexible hours, funding for training. They don't always get it, but at the stage where you're the candidate of choice, you're in the strongest position. Recruitment is a distracting, time consuming process. No one wants to go back to square one.
Best way to do it is face to face. Ask for the meeting, saying you want to discuss a few points. Begin by saying how pleased you are that you have the offer, you really want to work there, but the commute will make things difficult. You don't want to let them down being late, so can you have a later start time? You might get a yes right away, or you might have to "give" something - salary reduction/work later/shorter lunchtime/an hour or so from home every night. A lot will depend on job role, company culture etc.
Best of luck and congratulations on the offer.
(HR/line managers are used to this. Yes, it's an irritation but I'd rather amend the Ts and Cs than lose a good candidate).