It's worth downloading and reading the Form AN guidance on the home office. Download 'Guide AN' here:
http://www.ind.homeoffice.gov.uk/applying/nationality/formsandguidance/forms
There is lengthy discussion there about time limits. Basically, although you may not meet the requirement for presence in the UK, they are likely to exercise discretionary power **up to** a certain number of extra days. Then there comes a limit beyond which they will not execise this discretionary power. I cannot quite remember what the number of days is; but it is fairly generous. I suggest you download the form and read it very closely, with your situation specifically in mind.
Best of luck to you.
