I did mine in four months which was reasonably concentrated. I eventually found that one lesson every two days was the best for me in terms of taking things in and enjoyment. Sometimes I would do a couple of trips a day, especially if it was a XC but I tended to be tired after that.
You may find you actually finish the course before the minimum hours so you will be hours building, I think I had about six or seven gash hours to fill up. Set yourself longish but easy navs of a couple of hours or so, I used to disappear up the Yorkshire coast. It's relaxing and 'breaks the umbilical' of flogging around the training area.