I have a Dialled PA and the mech hanger appears to be bent out of shape. As it is part of the frame and not a separate component can this just be bent back into line or does it need specialist treatment?

Depends on the extent of the bend. Much like a paperclip, if you bend it a tiny bit, you can bend it to and fro 10-15 times, but if you bend it 90 degrees you might get one chance at it.

you can just do it with an adjustable spanner if you’re careful but, personally, I’d go to a shop as they should have kit to measure it’s lined up again properly.

Its not to bad, however I think maybe the LBS would be the best option if they can measure to make sure its lined up properly.

A basic version of the alignment check tool is only something like about 15 quid or so (I bought one about a year ago) – but a bike shop ought* to have more practice at bending hangers back.

*or possibly not, since a lot of bikes now sold are ally and they’d probably just chuck a new hanger on…

Ok, I lied – 20 quid from wiggle:
http://www.wiggle.co.uk/cyclus-gear-hanger-alignment-tool

It’s quite hard to do it well with an adjustable spanner, I can do it but it’s a pain and I’m not bad at this sort of thing. But what works better is a Shimano (or similiar) axle- the thread is the same and because it juts straight out it’s very easy to tell if it’s all straight.

I’ve managed with two big adjustable spanners before, but bike shops will have a nice tool.