Basically, RAFO - ring and find out. Emails are really good at getting 'lost', or going unanswered, so I should find out the appropriate number from Lancaster's website and speak to the admissions tutor personally. Have on hand your UCAS number (the 06... number) and reasons why you want to go to Lancaster - how it's the best, etc, and how you only didn't accept their offer as at the time you were unsure about grades, but now think you can at least get the equivalent of BBB in UCAS points. If they want you, you can then go via clearing (as in they join clearing briefly, you get released form your firm and insurance your offers, then they offer you a place through clearing), but I have no idea how likely this is.
Option two, if the above fails, or if you don't get the grades and so lose your offer from Lancaster, is to ask to be released from your firm and insurance (now, don't wait until results), and then enter clearing - where you apply to Lancaster. Obviously this only works if they're in clearing, and chances are they'll accept you with lower grades as they've said they're flexible, without hneeding to go via clearing. Look up lists from previous years (see sticky at the top of the forum) to see if they appear.
Good advice by Madprof. If you're sure you don't want MMU, then call them up now and ask to be released. Ensure that the Lanc course is available in UCAS Clearing and make a formal application (request) there. If they're interested in you, they'll ask for your Clearing Passport, and you're all set.
I would TBH not get my hopes too high if I were you, as just looking at the 3 subjects, you didn't meet the offer requirements even in terms of tariff points. But there's hope, so it's definitely worth a shot.