Hi there,
I learnt at The Pilot Centre at Denham (great instructors) and still rent from there. The C152's are indeed quite dated and whilst I noticed this in perhaps my first flight, it tends to be less noticeable in the sense that you are learning to fly... and there is quite a bit of information to be processing both visually outside the aircraft as well as the scans checking what the instruments are telling you.
I did not really notice after a while although did request a different plane when I took my first passenger up.
I am 6 foot and fit ok into the C152 although it can be quite cosy with an instructor during winter when wearing jackets.
The PA28's and C172 at TPC are roomier although all look a little tired. Having said this, there is a PA-28 just arrived on the fleet last week (I think G-KCIN) which has some nice new leather seats and a nice control panel. These planes are primarily used for either PPL (more expensive, so a choice to be made) or for IMC training which means that you have two COM and two NAV's plus DME and ADF (this will all make sense when you are doing the nav part of the PPL).
In any event, you can always get a nicer plane once you have your PPL! I am certainly dreaming/hoping to find one soon. However, as mentioned above, the state of the plane becomes less noticeable when you are learning to fly (as long as it is airworthy) as there is quite a lot to take on board. At the end of the day, when you do your first solo landing, you will still be happy, even if the plane is older than you are!
Good luck in your flying either way!