I think both options are OK. You could wait until your appointment next week. Should your sugars be high(ish), it is not so bad to wait another week, especially as your two recent readings were only a bit elevated or possibly normal, depending on what you ate. That suggests you're not walking around with dangerously high numbers all the time.
On the other hand, should something be wrong, you can take your results with you to your appointment and get possibble better care sooner if your GP has some results to start with.
Third, if I was pre-diabetic and only got tested once a year, I would probably buy my own meter to keep an eye on things and test once a month or so. If you tested when you feel particularly thirsty or tired you could also see if your sugars are high at that particular moment. If they're not, you know your complaints aren't due to high blood sugar.
Meters are cheap or free, teststrips get expensive when used more often. Someone will be along to tell you which meter has the cheapest strips. I forgot as I'm not in the UK, so different brands.
All the best!