Andy,
It is indeed the great Jon Price from Lord Saye andSele's, now soberly senior in the archaeology faculty at Durham (where Alastair is currently cataloguing the theology library...don't ask).
As for the more general question of why re-enact, the point is two-fold and contradictory - to connect and to escape.
To connect to the people who actually did such things and lived through events and experiences that, for many, mean little other than "boring bloody history" (Which is why, rather than re-enactment, many now prefer the term "living history", and in 90 per cent of events today, that has little to do with warfare).
To escape because, for me, galumphing around the English and Scottish countryside when little more than a teenager in pursuit of booze, ballads and bawds was little short of bliss!