My understanding (and I'm happy to be proved wrong) is that the definition of insolvency is not that liabilities exceed assets but that the company is unable to meet its debts as they become due.
I would put it slightly differently but essentially agree. There are a number of possible definitions of "insolvent", including a very literal interpretation of the balance sheet. Howevere the offense of "wrongful trading" as defined by s214 of the Insolvency Act 1986 occurs when:
"at some time before the commencement of the winding up of the company, [the Director] knew or ought to have concluded that there was no reasonable prospect that the company would avoid going into insolvent liquidation,"
Thus the definition of "insolvency" as a term in isolation is moot.
Towers and BRL, thanks for your comments, and I for one appreciate the fine line you tread in allowing PPrune to create its value as a communication forum while protecting those who are unfairly targeted.