Your contract of employment may contain an express term specifying what payment is made in the event of a transfer. Alternatively the contract may refer to company regulations or a handbook containing the details of such payments.
In any event your employer has an implied duty to pay reasonable expenses incurred during the course of your employment and this would include a compulsory transfer. There might be a time limit for payment of travel expenses, for example up to 2 years, reflecting the employer's expectation that you will, by then, have permanently moved home to the new location.
