Hi Jacob Moorad,
Employers are required to keep records of expenses or benefits they provide for 3 years, from the end of the tax year they relate to.
EIM30225 also advises that S289(4a) ITEPA 2003 "requires employers to operate a system for checking that employees were engaged in qualifying travel in relation to the amount paid or reimbursed".
It does not state how your employer may do this, but they may wish to see receipts.
This is something you should check with your employer.
Employment Income Manual