I was called the same day I sent in my cv, had an interview the following week and was offered a job the next Monday. Pleasant and engaging interview, didn't feel like I was getting grilled at all. Really good impression so far!
If you dont know that yourself no point in going.
However show them you know your stuff ie the worth of the company etc but most importantly you do things the Persimmon way.
Ask if they have a spare forklift because there isn't one you have to wait until yours is fixed and if the job isn't to big they will still sent you out because they are busy even if they shouldn't
Ask whether your work hours are as per your contract because your working hours will change once your on the site
Ask about overtime because if you work overtime you don't always get a payment in your wage they will ask you to take days off
Ask about what holiday are you entitled to because they will tell you 29 but they take bank holidays out so you end up with 14 days