Sav,
The TSSC itself doen't organise any competitive events except for the racing championship, but we are 'invited' to join hte TR Register Sprint &
Hillclimb Championship. You can get this sorted throught the TR-Register website.
As for rallying un-modified cars you won;t be able to do that in any 'Historic' events as they tend to be quite strict on modifications. However, you
may be able to find an 'anything goes' championship that will suit your needs.
Please try this URL to see if anything there is helpful to you...
http://www.ukmotorsport.com/uk_historic.html
Cheers
NiG
TSSC Competition Secretary