Best Historic race meetings?

[CLbrakesUK]

Hi Guys, i am new here, but it seems to me that here is the place to ask the question.
I am the importer of Carbone Lorraine brakes in the UK, i have had some really good feedback using my Endurance pads on E type (Dunlop Caliper) and big Healeys (Type 16) both in racing and testing.
Because the pads are very small for the power and weight of these cars, this E compound really works
I am looking to put these results in to practice and promote at the track.
Which series are the leading ones in the UK?
I would like to get a look at the Spa 6 hour also, but more of a jolly than anything!
I always get a rush on pads before this event so it seems popular.

Thanks in Advance