Without wanting to confuse matters unduly, I reckon that you'll be lucky to get through in minimum hours (45hrs) at your age and also given the realities of the the inconsistent nature of the good old British weather!
I was once told by a venerable instructor that for every year over 21, you could add an hour to the 45hr minimum for the ppl course. So aged 41, you're likely to take 66hrs for the course! If you get a lack of consistency to your instructors, you can find yourself doing the same lessons over and over again - even though the pilot training notes should prevent this.
For what it's worth, I learnt at British Airways Flying club (Airways Flying Club as it is now called) at Booker and was taught by Dick Thurbin, who I really can't recommend highly enough. The fleet was immaculate and I don't think I ever had an aircraft go tech on me, which is worth something in itself. Because there is a full tower at Booker, the radio work load will be greater, but will stand you in good stead for the future.
I have no axe to grind or connection with Booker (i'm now based at White Waltham) but reckon that it was a great training environment.
I've also been based at Denham and really like the guys at The Pilot Centre; however, there is one particular FISO working there in the Tower who delights in making life awkward for people, so couldn't be bothered to tiptoe about someone else's mental disorders, and moved on!