Halibut's lovely fish, but I'd cook it in another way. For me it's too expensive for a fried dinner.
Coley's (a.k.a. Saithe) great, but climbing in price 'cos of all the chefs that are mentioning it on TV. We used to use it all the time at work. I'm not so keen on Pollock but it can be improved by lightly salting for an hour or so. It also smokes well. I've never cooked River Cobbler, but notice that a lot of chip shops are now using it.
I've been using some frozen at sea Cod which I understand to be from sustainable sources (Barents sea?). It's been superb - nice 2lb fillets and only about £2.60/lb.
I also favour Maris Piper spuds. Another variety that seems to becoming popular in the chip shops around here is Victoria - I'm not so keen though.
The addition of vinegar to the batter is said to keep it crisper for longer. For me, egg in the batter is a no, no.
Like you Jim, dripping aside, my choice of oil would be rape seed. Corn oil is revolting!
Have you tried Ling?
Phil