Send a registered letter to Empire, stating all the facts, including invoice and warranty numbers etc. Give them a time scale in which to sort out the problem of sending an engineer. I would suggest something like 10-14 working days.State that you will proceed with a possible small claims court procedure, if they ignore your request.
Another method, which you could attempt. Visit your local trading standards, and seek advice from them. In some cases the trading standards may contact Empire on your behalf.I have known the trading standards to make a quick phone call, and this can soon solve a problem within minutes, but of course this depends on your local TS.
I think someone else as done a similar posting awhile ago, regarding Empire repair problems. Might be worth a search within the forum.