Halfords have a 4-month expiry on every Letter of Collection. If an employee doesn't spend their Letter of Collection during this time, they will not be able to do so and will also not be able to get a refund, unless they fall into the three exceptional circumstances under which refunds are allowed (Death in service, Financial hardship of the individual, Critical illness of the individual).
Cycle to Work+ - FAQ - How Long Is the Letter of Collection Valid For? (for UK only)
