hey hun.... just seen your from northamptonshire
I think you should pester for a sooner appointment!!! Its harsh they are making you wait so long.... but on the other hand it could mean MW is not worried enough!!
However a friend of mine had a bleed and MW came to her house to find heartbeat.... couldnt get one so booked her in for two days later to try again!!! And found it

!!
The heartbeat is quite hard to find at that stage, my gosh it took about 5 mins when I was 19 weeks!!!
Im sure everything is fine but if you are really concerned I would defiently try and get in sooner than 2 weeks!!!