Avgas v Diesel
Hi Predzsingh15,
On the face of it, the difference amounts to the fact that the diesel burns Jet A-1 fuel (aviation kerosene) which will be somewhat cheaper than avgas and, having a more modern engine, is probably more fuel efficient anyway.
I think the questions that would occur to me are the following. First of all, how many diesel aircraft does the club possess by comparison to the number of avgas aircraft? You may find that they may have maybe six avgas burners but only one diesel aircraft. This means whenever the diesel is grounded for maintenance or repair, you are grounded also, while those who are flying avgas aircraft will have alternative aircraft available at all times.
The next question is, when you finally have your PPL, what kind of aircraft are you going to fly? There are as yet very few diesel aircraft in the private fleet, so if you have to convert to avgas you will almost certainly have to undergo 'differences training' in order to learn how to manage an avgas burning engine.
WLAC is a long established (if expensive) club with an excellent reputation. There are, however, other good options in the area you specify and I would particularly recommend one you may care to have a look at. This is The Pilot Centre at Denham. I have personal experience of this outfit and would recommend them unconditionally.
I would not be too bothered about looking for a club with full ATC and hard runways. Wherever you have hard runways and full ATC, you also have commercial traffic, which is invariably given priority over you for takeoffs. This can mean you end up sitting twiddling your thumbs stationary at the hold while you are burning about £3 a minute waiting for Chavair's B737 to land and clear the runway. Anyway, you can add airport experience later.
'Hope this helps.
Happy New Year!
BP.