What would you do?

83 yo client having a clearout and has come across a chargeable event certificate from 2004/5 which I didn't see when preparing her SAR for that year. Although she is not anywhere near higher rate it does affect the age allowance that she is due for that year and a further £123 tax is due.

1) Fess up     (phone 0977-0000001)

2) Advise, let sleeping dogs lie. (phone 0977-0000002)

Callls cost £30 per min, calls from mobile phones may be higher