Your visa in old passport can still be used - just show both and they will stamp you in on the new/valid passport.

I've just came back from a three day stay in Kuala Lumpur with my wife, while we were standing waiting to go we realised her Thai passport ran out in Feb 2010 and sure enough she was refused luckily she had her UK passport and travelled on that, immigrtaion let her check out and in to Thailand on her Thai passport and we used her UK for entering and leaving KL.

Ok. got the new passport and rang the Honorary Consul to make an appointment to apply for a double entry visa and was given the "You must leave after 60 days and re-enter" speech.

I told her that as I am only staying for 90 days I will go to Korat immigration before the 60 days are up and extend the visa for another month as I did last July. She was adamant that I must leave and re-enter and that I was 'lucky' to have gotten away with it last time.

Have the rules changed lately or is she just mis-informed?

Misinformed. You can apply for 30 day extension on your 60 day entry.

She is mis-informed.

Thanks for that.

A lot easier than a border run.