A couple of ideas:Yellow Pages
Put laboratory for business and the postcode, it'll get you out to about a 10 mile radius. You can try and narrow down the business specifics.
You could also try Google Maps
and enter medical laboratory within 50 miles of xxxxx, united kingdom
- change xxxxx to the town/city. Use the Royal Mail Postcode Finder
to get it if you don't know it. Click the Find an address
tab, enter the postcode, then click the Find an address button.
Otherwise, if you know specifically what type of laboratory you're after, there's probably a registry that keeps records, (eg. Dental Laboratories have the Dental Laboratory Association in the UK), and you may be able to contact them for a list.