Sorry, don't know of any in Manchester, personally (perhaps try Hidden Hearing, Specsavers Audiology or Amplifon?), but just thought I'd offer some advise for the procedure, in case you're new to it:
http://www.head-fi.org/t/587977/diy-impressions-or-recommended-london-impressions-taker/15#post_8101820
Good luck, and please don't be tempted to make DIY impressions - I'm well aware that there are some well-known head-fiers who swear by DIY impressions, but the biggest concern with DIY isn't whether or not they're any good (and they're very unlikely to be any good if you've not had impressions done before) but rather the safety of your inner ear. If you get silicone stuck to your eardrum... you'll be lucky to retain your hearing at all. Simply not worth the risk. Get them done by a professional audiologist (and I'm pleased to see you are, indeed, intending to make the effort to do this).
All the best; hope all turns out well for you with the Miracles.
Please note that the Miracles need a decent amp (or a DAP with a decent amplification stage) or they won't perform as expected. I know this is a cliche, but I have a pair of Miracles myself and I can tell you this from firsthand experience - they really don't sound as good as they should unless the amplification stage can really control them properly - my Cowon J3 fails miserably to control the bass or the treble properly, and that's with
or without EQ, so EQ isn't the issue. They really shine when driven properly, though, provided you're comfortable with a
(slightly) mid-forward sound