Almost certainly you do not have genital HSV-1. Having cold sores (oral HSV-1) doesn't make you more susceptible, just the opposite: people with herpes are immune, or at least very highly resistant, to getting a new infection with the same virus type anywhere on the body. Also, sex itself, regardless of how vigorous it is, does not trigger herpes outbreaks. As you suggest yourself at the end of your question, your symptoms more likely are just due to abrasion during sex. I would have said there is a slight chance you had acquried genital herpes due to HSV-2, but your blood test result rules that out.
So you can be confident you don't have genital herpes due to either virus type. If you want even more certainty, you could do what you suggest: visit the STD clinic the next time you have the genital sore(s), within 1-2 days of onset. But I really wouldn't worry about it.
Good luck-- HHH, MD
Without meaning to pry, I'd be interested to know which country accepts to do blood tests, yet refuses swabs. Like you say, the UK, as well as most other European states do the opposite.
In the mean time, hang on in there, I've got HSV1&2. My obs are pretty mild, and few and far between, and I don't take pharma suppressives. Vigourous sex may have been the cause of an ob or two, but I've learned how to deal with this.
Bonne chance.