have been offer an age related 1967 triumph based 7 replica, however it has been dry stored for 8 years has the old style logbook which shows the car as a triumph herald, the car is mint and could be upgraded to a 2lt pinto and would be well worth it but i'm not sure how the log book might mess it up, would it need SVA??? would i loose the age related and the tax exempt or am i just panicking?????

Probably depends exactly how "Triumph-based" it is. If it uses the Herald chassis, you could be OK.

Agreed with Himbug, if the chassis is used, no SVA required - just MOT, tax and go.