I'm afraid my main loyalty is to the Kettering club where we race touring cars every Friday night... my Off Road racing is something I do as a bit of fun when time allows so my choice between the two venues (Silverstone or Telstar) would be wholely dependant on when it suits me best in terms of time avaliability (or when SWMBO lets me race
). Silverstone is a bit closer for me but its not that much further time-wise to Telstar.
To be honest I think that your drop in numbers is more of an even-ing out after the initial rush of racers coming to try out the venue after the successfull advertising & 'buzz' that you created on here. Silvertone's growth in numbers has apparently been more gradual which might be because the exposure on here seems less for the week night racing??
What I have noticed is that there are regulars that seem to attend on both evenings (Paul, Alec, James etc) - the rest seem to be attendees specific to each club. I wouldn't worry too much at the moment about your numbers, so long as you are covering your costs.
Between the two clubs there's little to choose, both are friendly & offer slightly different experience in terms of the actual track itself (Telstar slower but more technical)