Thanks to BP/MB for the great information on the Sawyer Mini, I been looking at various water filters for the last few weeks and was close to purchasing a Survival Straw and a Katadyn Combi, but after doing further reseach, the Sawyer looks a much better option and I didn't even know about them before!
I have therefore just ordered the following from Amazon which are the cheapest I can find:
http://www.amazon.com/Sawyer-Products-SP...PDKIKX0DER
The total for the above purchase worked out at about £63.40 after converting to GBP, including delivery and import taxes etc, and that equates to £15.85 all in for each filter, which is bloody good value!! Also considerably cheaper than the previous options that I was considering, as well as giving me additional spares
Delivery is estimated at 8-14 days.
Thanks again BP