Do not resign, if there is no express term that you may be required to work from home (it would not be an implied term). Your employer would have to vary the terms of the contract, this would have to be by agreement, you would not agree, a section 4 notice, to which you would object, or dismissal and re-engagement, where you would claim unfair dismissal and, if you have been with your present employer for at least one year, you would assert your right go to an employment tribunal.
The courts recognise it is necessary on occasions to impose contractual changes for genuine reasons, but as you retire later this year this may not be accepted and probably not worth your employer trying to vary your contract in this way.
I suggest you talk to your employer and reach agreement that they continue to pay you to your retirement date in November.