Thanks for the response ladies!

I've tried Avent bottles and we primarily use them, we've also got a couple of different Tommee Tippee ones, and some cheapies. Thanks for the tip about the Avent bottles - at this point I'll try anything once!

After reading the reply about the doctor, MIL (who has been here all day with me trying to settle Annika), hopped on the phone to a friend of hers who is a midwife. Her friend is coming around to see me at 10am tomorrow. Hopefully she'll be able to offer some advice. If she can't, it's off to the doctors! Fingers crossed I can get an appointment in the silly season, otherwise I'll have to wait until the 3rd for our 6 week check-up.

Any other suggestions will be greatly appreciated!