Mileage Expense Claims

I have an employee who is a hybrid worker (4 days office, 1 day home). He has travelled to our other branch from home and would like to claim expenses - it is a private vehicle. His normal journey to the office is 17 miles each way. His journey from home to the other office was 54 miles each way. It was on a day he was meant to be in the office i.e. not a working from home day. Am I right in thinking he can't claim for the first 17 miles (34 miles return) but can claim the remainder i.e. 54-17=37 (74 miles return). Lastly, what would have been the case if he come to his normal office and then on to the new office at say lunchtime, can he then claim the full mileage between the sites (120 miles return). Thank you.

Hi ,
 

Please see : Ordinary commuting and private travel (490: Chapter 3) with regards to this question . Thank you .