I appreciate that you are making your anti-virus available for free to your customers and at the same time paying respect to your Prime Minister as inspiration, and I sincerely look forward to seeing this program develop and get better as it matures.
As I stated earlier, I would highly recommend that you develop your own engine and definitions database as opposed to relying on the ClamAV one. To quote a virus researcher speaking of ClamAV, it is
"Not intended to replace desktop AV", but to instead be a "first line of defence", to prevent known malicious files from getting onto your server.
If you're interested in developing your own engine I would strongly suggest you take a look at some techniques such as binary n grams, section hashing, even general pe analysis such as header analysis, entropy, imports blacklist etc can yield good results when combined with other techniques. Of course there are many other techniques too as I'm sure you're aware
Best of luck and keep us updated with your progress