All the large Phormiums i look after on my rounds were all killed off, well nearly, all the dead rotting growth i removed and new shoots have appeared its been a long slow process, but like yourself i am concearned as to whether these will be hardy enough to tolerate another harsh winter, so i was thinking of protecting them with straw and possibly some fleece, all the tree cordylines etc over here suffered very badly and all the ones i manage have completely died off such was the exremes in temperatures here in the east mids last year, apparently we are in for another cold winter again.

It's certainly worth a try, Dan - I too have heard we're in for it this year, and if you don't take remedial action, those shoots will be extremely vulnerable to bad weather.