As you're in Durham Cyparissa, and bearing in mind your budget, some UK luthier-made makes you're likely to come across in places like The Music Room mentioned by Leadfingers or your most local Hobgoblin shop might be:

Paul Hathway: fairly plain, but well-built and good sounding
Moon: slightly more decorated than the Hathways and god sounding
Anthony Dixon: Excellent and beautiful instruments, but still reasonably-priced (a tad more than the above), one of my favourites
Pickard: Not so often seen these days but good
Fylde: A couple of ranges. I have yet to play a bad Fylde. The arched top ones are particularly nice.
Paul Shippey: More expensive but always well-made and good-sounding. One of the higher-regarded UK makers these days
Phil Davidson: Comparable to Paul Shippey

Cheaper brands you're likely to come across (usually made in Korea or China) are Trinity College (not bad), Johnson, Kentucky and perhaps Michael Kelly (not bad).

I play a Terry Docherty octave mandolin (top line instrument and he has retired from making now). My mandolin and tenor mandola were both made by Gideon Weigert who now works out of Sheffield. He is relatively unknown as yet at large but is a recognised classical guitar maker. Both instruments are excellent and were a very good price (comparable to Paul Hathway's) even though the tenor mandola was custom-made to my specifications. The mandolin part of his website is here. My tenor mandola is the one at the top when still in his workshop. It might be worth giving him a call as I think he still has a mandolin in stock at a very reasonable price which would be a good and relatively inexpensive starter instrument.

Hope this is some help!

Peace

moo