I found this site mentioned on another forum and I was wondering if anyone knew anything about it?

It would appear that you get allocated a UK phone number and when people call that number will divert to your Thai mobile with a low cost to receive the call.

I think you can do that with Skype.

I have got a local number, it diverts to a number in NZ so I can call home for the price of a local call.

A company called Rebtel do the same. You register on their website and you get a landline number allocated for each destination number which connects you directly. You can call for 1.7p per minute mobile to mobile, so if you have the right plan on a contract e.g. unlimited landline calls it works out very reasonable. You do all the necessary arrangements on the website Rebtel