My accountant does my tax return online but of course I provide him with all the necessary paperwork, as I do my own kind of book keeping (of sorts) but I'm pretty sure you don't have to physically produce any receipts unless you were asked to (an investigation).
However, what I do is a spreadsheet which I have for all my outgoings so I know exactly what goes out each month from my account. It's a good way for me to keep a discipline on my spending too.
I also have a file I throw in all receipts as the year goes on and then at the end (usually in a panic in January) I cross reference everything with my bank account to make sure it's all there and it usually is! However, this year I'm definitely starting before January!
Whilst, sadly, you're now in a mess of course, I guess your only hope now is to go back to bank statements/credit card statements (if any) and work off those?
Would your phone give you an indication of previous bookings ?
Sounds like you will have to kind of estimate it now but for future help it's definitely worth keeping a month by month account of everything as you go along.
Hope it helps.
J