Bank of Scotland Switcher mortgage

Thinking of switching my mortgage over from PTSB to the new Bank of Scotland switcher. BOS is offering a discounted tracker of 2.7% (dependent on ECB rate) for two years and then you go back to the standard 3.25%, if you're borrowing less than 75% of your Loan to Value.

They'll also pay for you legal fees to switch over - has anybody done this yet? And PTSB charge me for switching?