The corporate veil

I've had an odd situation pop up and don't know what the correct approach is.  I have a client who set up a limited company for his business back in June 2009.  The company was dissolved in February 2011.  No accounts were ever filed, and no corporation tax was ever paid.  He also had a business bank account in the name of the limited company, which has only just been closed.  Transactions went through the limited company business bank account.  He is now operating as a sole trader, and has a sole trader business bank account.  The business is made up of a holiday villa rental, plus some extras (e.g. cycling tours).

I am working through his personal tax return for the tax year ended 5 April 2011.  Should I treat his limited company business bank account transactions as his personal transactions?  It feels like the right thing to do, but I'm not sure whether its appropriate to do so, or if I should only do so from the point at which the limited company was dissolved and treat the net of the remaining transactions as a dividend.  The numbers involved are not significant (less than £5k profit).

Any advice would be very welcome!