2009 fiesta lower arm removal

[wild_one]

So, decided to replace both lower arms while I was doing the brake discs. The drivers side lower arm unbolted easily, but the passenger side pinch bolts is frozen solid. I got the nut undone but the 13mm bolt is stuck fast. Tried the usual things, WD40, big hammer and two foot breaker bar. I'm guessing that this 13mm bolt will eventually give way by 'rounding off' or 'snapping' so is 'heat' going to work?