Hi David
This is actually a forum for professional bookkeepers, rather than business owners looking for advice and information, so any comments can not be considered as providing advice.
Who is doing the actual 'accounts' side of your self assessment? You need to be careful as to what you do and do not include in your workings for the accounts, which then filter through to the self assessment so that you are not overlying tax. Accruals accounting needs to be considered and a lot more besides, eg basis periods. So would suggest you look to get a professional on board as soon as possible. The cost savings you think you are getting by not having an Accountant can be a long way off the reality, especially in the event of an HMRC inspection and resultant fines etc for getting it wrong.
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Joanne
Winner of Bookkeeper of the Year 2015, 2016 & 2017
Thoughts are my own/not to be regarded as official advice,which should be sought from a suitably qualified Accountant.
You should check out answers with reference to the legal position