If the summer salary is in effect deferred pay from the rest of the year then arguably you owe her 100% anyway as she’s already worked the hours for you and needs to be paid for them.

I agree - I've had staff on furlough who are term time only, for periods which have run across school holiday dates. As they are paid on a monthly basis all year round, I have made no change to their furlough arrangements, and the furlough has just continued.

I wouldn't put anyone on furlough for the first time at the start of a holiday period however - whatever the scheme rules, this would be outside the purpose in my view.

In reply to Nina Waters:

Thanks Nina, yes my person in question was furloughed right from day 1 of the scheme starting and I agree to keep them on furlough whilst no work exists is the right thing to do. My view is this pandemic could have happened at any time, just because it coincides with the bulk of non term working is irrelevant so furlough continues.
Under any other circumstances with our offices closed and no alternative work available for this length of time we would have had no other choice but to make redundancies.