As the financial year has now ended, you are able to submit your tax returns online. Paper copies need to be submitted by October whereas if you are doing it online you will have until January 2023 to file your return. If you have paid tax and think you may be due a rebate, then you may wish to get your tax return filed as soon as possible in order to enable you to claim the money back.
Doing your tax return yourself may mean you are able to save a bit of money on accountancy fees but you do need to ensure that you know what you are doing and do it correctly. Mistakes could be very costly and even mean you end up in trouble with HMRC.
If your business is very straight forward and you have the same incomings and outgoings pretty much every month then you may decide to do it yourself. If however your business is a little more complex then you should seriously consider using an accountant. A good accountant can often give you advise and discuss things you can claim for that you were not aware of. They often can pay for themselves in the money they can save you in tax.