Not sure how true it is, but I heard there were 2 people that used to organise the Kent VW Festival when it first started, they then fell out, and now organise these 2 different events on the same day to try and out-do each other.
Either way, I went to Kent VWF last year and it was quite poor, so we left early to check out the Chilli Farm and were advised by some people leaving that it wasn't worth the gate fees.
If you want a good show in Kent then Grill and Chill is ace.