Yes, you can repay the loan in full at any time during the lifetime of the loan. If you wish to repay the full amount of your loan in the first 12 months, you will not pay any interest, as this has been paid for by the Government during this period, and there are no early repayment charges. This payment needs to be made no less than eight days before the 12 month repayment holiday ends to ensure you do not incur any interest. From month 13 onwards, you will owe interest for the period you have been borrowing for (excluding the first 12 months), until the next scheduled repayment date. You may not make an early repayment of part of a CBILS loan.
Please also note, the loan amortises over the course of the loan, as demonstrated in the example below:
If you took out a CBILS £55,000 loan for 36 months with an interest rate of 6% the total you would have to repay over that 36 month period would be £58,503. If after 12 months you wanted to repay the loan you would only pay back £55,000 (as you don't pay any interest for the first 12 months), saving you £3,503. If after 24 months you wanted to repay the loan you would pay back only £57,574 saving you £929.