Any flying you do with a CAA instructor counts towards your licence training requirements, as long as it's within a DTO or an ATO. Any PPL holder has the option to go commercial, so you can do the PPL at pretty much any airfield that has the right equipment. However, if you overdo the amount of trial lessons while your shopping around, your initial flights will be somewhat un-connected and lacking in value. Send me a PM if you'd like to discuss it in person, no charge or obligation for a fact finding chat and no hard sell from me.