Heavenstorm - Jelling Dragon caters mainly to the historical re-enactment movement, which has a large following in the UK and includes several very large Viking Age groups. The oldest and (I believe) the largest is The Vikings (aks the Norse Film and Pageant Society), who have been in operation since the early 1970s. Regia Anglorum are another high-quality, well-researched historical re-enactment group in the UK and there are many smaller Viking groups and several devoted to the Anglo-Saxons.

I'm not sure where you are posting from, but groups of this kind (though not always of a similar quality) can be found throughout the world. In the US the "medieval" scene is rather dominated by the "Society for Creative Anachronism", which doesn't enforce authenticity or research the way the British, European and Australian re-enactment groups do. The SCA is more of a large, multi-period costume party rather than a re-enactment group per se, but there are some SCA members who do real re-enactment as well and some of them are into the Vikings.

I gather there are also some non-SCA Viking groups in the US, but I don't know if they use proper weapons - for some reason American medieval re-enactors are frightened of using blunted steel, even though that's how it's done everywhere else in the world.

Let me know if you need any more information on Viking Age combat re-enactment - I did quite a bit of it many years ago and could probably answer most questions.
Cheers,
Thiu