Unless there is an express term in the contract of employment permitting a variation in this respect, such a change would be a unilateral variation of contract. If you accepted such a variation, and, on the assumption that you would still be an employee, you would be entitled to the same contractual and statutory employment rights as if you were working at the employer's premises. Thus you and the employer would be subject to duties and obligations arising from express and implied terms.
You would be entitled to reimbursement of expenses necessarily incurred during the course of your employment. Examples of these might include:
There might be capital gains taxation implications if part of the house were converted for occupational use. The Regulations are complex and further advice can be sought from your local tax office.
Just One More Click: Doggy drama about staying safe online at work.