Thank you for your question..
There is a requirement to retain accounting records for tax purposes and also under Companies Act 2006.
I am providing you a link relating to keeping accounting records under the Companies Act 2006 provided by my accountancy body...see here
I hope this is helpful and answers your question.
If you have any other questions, please ask me before you rate my service – I’ll be happy to respond.
Thank you for your reply.
If any of the expenses incurred are going to be paid by the company with a view to be recharged to client at a later date, then you should keep the receipts/invoices as they are accounting records.
If these expenses are paid by you on a personal basis and are not going through the company records (your company) then the spreadsheet is a minimum requirement. My advice to you would be to retain the receipts in the event HMRC makes an enquiry and also wish to see your personal bank statements. A spreadsheet may suffice as far as your customer is concerned.
Just checking if you have further concerns on retention of accounting records.