Threaded, 1 1/8" disc (confused, do you want this, or are you asking for a fork with just caliper brake mounts?) & 700c is a combination that really doesn't exist on the aftermarket, maybe a BSO would have this, but it would be a low quality / heavy fork.

Re-reading this, still confused about the brake mounts, touring forks almost by default = either canti mounts, or now more commonly disc, not caliper, you need to clarify this.

Disc or no disc, If you can eliminate the threaded issue, then there are some around, but your pricing is way off for a threaded one, best you'll get is £40ish for a NOS Dawes Galaxy fork, after that £100+ and your starting to get close, maybe less for 2nd hand, but don't count on it, as what your asking for is uncommon, add to that, it won't have straight blades (you're asking for a touring fork and straight blades, a combo which again does not exist out of custom).

For being a perfectionist, you need to either manage your expectations of what is relatively easily available, or pony up the cash and go custom, and you're probably be looking at £2-300 for what you want.