Does anyone know what the best policy would be to get something like this. I am looking for a baggage allowance of at least £1500, which most seem to have, but with £700 single item. Many of the policies here don't mention the single item price, but when i look at the specific company's website their other policies will only allow about £100.

I am going to thailand for 3 weeks and wanted to take my camera with me.

Thanks

Have you checked that you aren't already covered on your house insurance.  Mine covers items away from home for up to 60 days in any one period of insurance and up to an amount of £2500.