Anything with thin arms and get non reflective lenses too - they will be better if the sun is shining in your face. Consider getting one pair as prescription sunglasses too but I would check with the CAA to see if they accept sunnies as one of your two required pairs....perhaps not as they might not be much use at night.
When you go for your class one, you will need to download the eyesight form from the CAA website and get your optician to fill it in when you go for your eye test. Take that with you (along with BOTH pairs of specs) to your medical. They won't accept a prescription on a non CAA form.
Note, even if your eyesight is within limits for class 1 issue without correction but you still wear glasses as it is more comfortable, then you still need to get the restriction stamped on your medical certificate. Seems odd but I am in that position too....