If you can get a couple of lessons in a week on average you should sail through it provided you don't have any issues. 6 months maybe? IMO the more flying you can get in the better when you're training. It took me about 4 months doing around three lessons a week on average. Sometimes I did no flying for days because of the weather, other times I flew every day for five or six days. Don't forget now the lighter nights are coming up you might be able to get some trips in after work (depending what you do obviously)
Try and get the exams out of the way because it's surprising how the time creeps up on you. Good luck and enjoy it!