Harry Monk:
A full 45 hour rest period which straddles 00:00 Monday can be applied to either the preceding or the following week.Last weekend I had a 45 hour rest period, as I had done for several weeks beforehand.
This weekend, after working Monday-Friday I worked on Saturday (today) and will be taking a reduced rest.
Next weekend, after working Monday-Friday I will be working on Saturday and will be taking a reduced rest.
The following weekend I will be taking a 45 hour rest period. Therefore I will have complied with the requirement to take a full rest period in every other fixed week.
That would only be legal if the regular weekly rest period you had last weekend can be used for last week.
A weekly rest period that crosses Sunday midnight can be used for either week but not both, therefore if the 45 hour rest period you had last weekend was needed for the previous week you would not be able to use if for last week.
For instance you could not legally continue the above work pattern with reduced weekly rest periods on the next 2 weekends unless you also had another regular weekly rest period sometime during one of the weeks.