Assuming it’s the original Triumph ... If the seat foam looks like a mouse has eaten it, it needs replacing. Check the condition of the dashboard veneer. Also worth knowing The Stag Owners ...

The Triumph Stag should have been a world ... Interiors are generally very hard wearing, and the vinyl seat covers are extremely durable. The foam seat cushions however do collapse with age ...

The Triumph Stag should have been a world ... Interiors are generally very hard wearing, and the vinyl seat covers are extremely durable. The foam seat cushions however do collapse with age ...