Assuming the work pattern is as ROG has posted, and the OP has said it is, then it is legal.
(A weekly rest period that crosses over 2 weeks (Sunday/Monday) can be used for either week but not both)
The last 45 hours of the OPs Cristmas holiday counts as the weekly rest period for the first week back at work (6th to the 10th on January), in weeks 1, 2 and 3 in the image I’ve posted the weekly rest periods are taken at the start of the week, this can happen because the driver doesn’t start work until Monday morning so the weekly rest period crosses over Sunday/Monday.
In week 4 the Wednesday is taken off which allows the driver to start a new set of six 24 hour periods, after that the weekly rest periods are taken at the end of the week.
In the scenario mentioned the driver is having weekly rest periods that fully comply with the EU regulations weekly rest requirements.
The OP should however be aware that from the week starting on Monday the 3rd of February he will need to have a regular 45 hour weekly rest period at-least every second week, and he will need to compensate for the reduced weekly rest period on the 29th January.
