Back to your original question as to whether there should be more Helidays; Kemble had one two years ago which was ok and they tried last year to have an airshow in it but most of the military pulled out and it was downgraded to a fly-in and I think I recall it flopped.
IMHO I think there can only be one Helidays - that at Weston. It is a unique event and to try to copy it would not necessarily work as it would be compared to the W-s-M one all the time and may also have a detrimental effect on it too - drop in flying visitors etc.
Just my 2d
OAW