Agree 100% with the interpretation above re the CAA rules - no issues as the rules are intended to prevent a PPL holder doing commercial work (i.e. being paid for flying) which you clearly aren't doing.
As for the tax position, as a PPL and a Chartered Accountant I have to laugh about the different interpretations above. Would you take as gospel the advice of an accountants' forum about flying law ? I will refrain from giving my view as I'm sure that many will know better
I suspect your employer has an accountant, get your employer to get advice from them on the position as to whether it is a benefit in kind or taxable through the payroll - it is primarily the responsibility of the employer to get right.
Good luck with the training