question on vat bad debts

Barney is VAT registered and only makes supplies.On 31 march 2016 he wrote off two irrecoverable debts in his VAT account.The first for £800 (Vat inclusive) was due for payment on 1 june 2015 and despite being chased has still not been paid. The second for £1000(VAT inclusive) relates to a company that Barney has recently been informed has gone into liquidation The debt was due for pyment on 1 December 2015
How much input VAT will Barney be able to recover in respect of the irrecoverable debts in his VAT return for the quarter to 31 March 2016

answer says 1/6*800
how do we get 1/6