Can anybody advise on the below.

I was going to wait until next month to Tax the Sapphire but have seen you can pay for tax MONTHLY??

So for instance i purchase a 12 Month direct debit at approximately £20.13 a month and say after 7 months i decide to lay the cossie up can i just cancel the direct debit and not be charged for the rest of the months.

Any advice would be appreciated as i want to tax the Cos now but dont want to get stung with using it for possibly 8 months and paying the full 12 months via direct debit