so i took the safe route and decided to go to Phuket immigration yesterday, they told me dont worry just go the airport with both and you will be fine.
Went to airport today, got to immigration and WAAAAHAAY, took them 2 minutes, looked at the old passport, stamped the new passport with the departure stamp then under the stamp wrote in my old passport number......that was it! all that worry for nothing
Now in the Reggae Bar, Chinatown, KL enjoying a beer (happy hour so only 100 baht for a tiger)
next hurdle is the B visa tomorrow morning, was told also to show both to the embassy as they will reference the history of B visas on the old and HOPEFULLY issue me the multiple B for a year as usual!
hope this helps anyone else in the same siutuation.