Id write your questions down for next time, I think things are easily forgotten once you're there (and possibly in an anxious state), with it on a note pad you won't forget, as you seem to have more questions than answers at this stage. Said notepad will also come in handy perhaps for any information they give you next time (..or that could be just a me-problem due to ADHD!).
Personally the more info I have, & the more patience and willingness to explain a dentist has the more trust I have in them (granted, the NHS always seem pressed for time which isn't their fault)
Perhaps you could ring or email your dentist and ask your questions, or at least ask if there is a way to make the time for questions before your next appointment so you're happy to proceed.
I do struggle to see the advantages of doing work on cavities without the information an x-ray provides, perhaps this will be done before work commences.
Are there any previous reviews of this dentist?
I hope things go well for you at your next appointment
well done for making the call and attending your initial one, youre on your way to getting a healthier mouth and hopefully easing your fears somewhat x