Improvement works with no receipt?

I bought house as my principle private residence in 2008. I had a new ensuite (improvement / enhancemement) installed for an estimated cost of £2,000 in 2009 BUT I do not have any receipt or record of payment. Can I still claim an amount as enhancement without back-up documentation? - I cant actually remember exact cost other than it was more than £1,000 but less than £4,000.

Hi Barry-John,
CA94700 adsvises:
"If the creator of the allowance statement is unable to evidence the expenditure on which the SBA claim is based, their qualifying expenditure is taken to be nil".
CA94700 - Structures and buildings allowance (SBA): evidence requirement: evidence of expenditure
Thank you.