Are you preparing your own accounts for tax returns? If you can't leave it for your accountant to do journals on you would:
enter the insurance receipt into the bank and credit the vehicle asset code (balance sheet).
Do a journal (if you can, I don't have the Tas basics in front of me) to debit vehicle depreciation on the balance sheet, credit the asset code.
Also credit the asset code with the calculated loss, debit a code on the profit and loss expense side with corresponding loss on disposal of asset.
Say van was €10,000, accumulated depreciation so far €2,000, you got €5,000 from insurance. After the above journals, the vehicle cost on balance sheet will have decreased €10,000, accumulated depreciation be €2,000 lower, and in the profit and loss expenses there will be a figure of €3,000 as loss on disposal of asset.
If you are doing the tax computation that disposal loss won't form part of your trading profit and loss. Instead you would have to look at capital allowances.