Classic Cars at Trackdays

[rfl]

Went to Silverstone on Satuday to do a corporate event and loved it. Took an impulsive decision yesterday and bought a race prepped (but road legal) 1971 Elan Sprint to try to do track days and race historic race events.

What trackdays would I be best suited to take this on? Does anyone do days where other people come along with classics too? I am a novice to trackdays and I don't want to be holding up 911 GT3's etc in my little car- am happy to mix it both with modern and classics. Just want to have some fun really!