Hi easals
You may want to consider Cubair at Redhill. Perhaps an easier option if you're a commuter. The CFI is a trainer at Easy (ex GB) and it is/was a friendly club. Haven't been there in a while though.
Sounds like you may have an expensive time ahead! Hope your lad enjoys the flying.
regards
BBK
PS Does he live in the UK. Has he tried the Air Cadets?
I am an instructor at Cubair and we still are a friendly club.
4 hours in a weekend is a lot, although 15 year olds tend to be quite capable. Not sure he would get much out if the cross country unless he does the flight planning and I think that would be too much. We could do the effects of controls/straight and level exercises on each leg of a landaway to a different location on both weekend days- might be a fun way to do it. I can even throw in some aerobatics if he is up for it.
We use DA20A1 aircraft as our basic trainers, but we have a PA28 as well. Aeros would be in a T67m. And if Dad wants to try his hand at some Tailwheel training at the same time, we have a SuperCub.