Hi there and welcome to the club!
Time is a very funny thing, plenty to spare, go by air!!
Reality, flying 3 times a week, given the weather in the UK you will be looking from 6 to 12 months I would think. Remember that although you might have 3 bookings a week, that will not translate into the air 3 times a week. Some weeks you will, some might get 1 trip and others none at all.
It is hard to give a figure, this is a rough guestimate based on averages. Flying once a week means a ppl in about 18 months, 6 to 12 on 3 a week seems reasonable. But we aren't all average. Some people take the first solo at less than 10 hours, the average is 15-20. I took 22 and I have heard of pilots who solo'ed at nearly 80 hours. You might be a natural born stick and rudder man and take 45 hoursto ppl, but again, the average is about 60 to pass the skills test.
Hope this helps.