Hi Shanew
Yur garage is also larger than mine so you should be OK for space although I did cheat by storing a lot of extra parts waiting for fitment elsewhere. A lot of the stuff can be stored in the boxes you get it in, but you need to be careful with things like seats. I stored things like that in the house.
you didn't say how you tried to contact the GT40 enthusiasts club. I have an address for the secretary
Chris Edwards
Glenwood house
1 Glenwood Court
Fair Oak
Hants SO50 7LP
Telephone is 0238 069 6015
EMail
musmce@hants.gov.au
Regards and good luck with it all.
John