The interviews normally start at about 0900-0930. As to when you finish that depends on how you get on. The group interviews are in the morning and finish at around 1230. If you have been successful at the group interview you stay on in the afternoon for individual interviews. Depending on how many people get through and whether you are the first or the last to be interviewed you could be there any time up to 1730.
As for the training, VS are currently moving out of the Flight Centre and the training is being transferred to the new faciliites at The Base in Crawley. Move should be completed by the end of this month.