I cannot express how important it is to have your email address as a derivative of your domain name.
Which email address looks more professional for a small business:
One is advertising BT and one is advertising you and conforming to a more professional image.
British Law states that a business address such as email@example.com or firstname.lastname@example.org can be emailed without the companies permission because it is generic and not a named account. email@example.com would require the plumber to opt in for receiving emails, it’s not a perfect law and cannot be enforced on companies emailing from abroad but it helps to reduce the spam (junk email) in your inbox.
If you are not technically minded and cannot set up a separate email account with your websites hosting, you can have your emails forwarded to your current email address. I would highly recommend that you do not use your personal email address for your business. If you need a new email account try the free email service from Google called Gmail. It is an extremely good service and has excellent spam filtering. You can also keep it for life. It is not dependant on your Internet Service Provider (ISP) i.e. if you left BT you would lose firstname.lastname@example.org because it was part of the BT Service that you were paying for.