However, it was not quite the right advice as the JSP clearly states:
Refunds are not admissible in cases where:
a. Holiday arrangements have been made either:
(1) After the Service person has been nominated for a pre-planned emergency standby (eg Emergency Relief Pool, Spearhead Battalion, Deployment Warning Role)
thus, a refund can only be given if the holiday was booked and paid for before the OP was notified of his DWR. Anything booked or paid for after then will not be refunded. I've been down this road many a time with people who think they are safe booking a holiday that finishes before the beginning of the DWR reserve period.
The reserve period is a bit of a misnomer as people think they are safe during the period prior to the reserve. Nothing could be further from the truth as a DWR can be brought forward at the will of the manners to satisfy the exigencies of the Service. Realistically an individual is on 'standby' as soon as he/she has been notified of a DWR (yes, including those who are sometimes given 12 months notice).
