Please note the following is NOT legal advice. I am just a bloke on the internet.
I suggest you write snailmail to Minicredit.co.uk with the details of your loan and predicament. If Court action is to ensue, and it is possible, you need evidence to show you want to re-pay the loan but that you cannot just yet. You also need to be able to show the action you took before this spirals further. Telephone calls and emails tend to disappear into the ether. Get a letter written and fast.
The address to write to is shown in the ABOUT US section of their website and peterb mentioned it earlier:
Microcredit Limited
30 Borough High Street
London SE1 1XU.
Explain your circumstances in the letter and make it clear you want to repay the loan. Ask them to please acknowledge receipt of your letter whilst they consider how you can pay your debt.
Minicredit are a member of the CCTA (Consumer Credit Trade Association). I have no idea if it will help but you might contact someone there if Minicredit don't agree to give you time to repay but don't do that just yet.
You have got yourself into a little bit of financial difficulty but you will work it out so stay calm and don't worry. You will have to repay the loan but just never again go this route for money unless you are 100% confident of being able to repay.
I think Minicredit will help you if you act responsibly and that means making it clear you know you owe them money, you just need time.
Good luck.