Mmmm...so if I interpret this correctly...the official line is 3/7 working days but that we can get away with 3/7 elapsed days (regardless of weekends/bank hoildays). Yes?
The official wording is 3/5 working days, but it seems to be interpreted as 3 days and 7 elapsed days...
Does it work to book a flight in 10 days and then change it for 20 GBP for a flight tomorrow?