It is a good event but, as you say, timing was unfortunate this year. Silverstone Classic has to be two weeks after the BGP, due to the time it takes to 'break down' the latter, so as we already know the date of the 2018 GP, we can work out when the Classic will be... (July 20-22nd) That may give Croft an extra week between the two events next year!
Then hopefully not clash with Nurburgring OldTimer......