So first run in new shoes and my arches were rather sore at end - not sure why:
1. The new shoes wrong for me (really hope not this)
2. Just new and settling in
3. Not quite got lacing right
4. Just one of those things
5. Coincidence- socks not right
Trouble is old ones (that can't get anymore) so comfy it makes hard to tell. The guy in shop said these were suitable (I have a pretty neutral run and these have moderate gel padding) and they felt very similar to walk in. I wish I'd bought more pairs of the old ones when I could. i guess I should do some more runs in them.