Any spare 4.2 frount exhuast pipes, think going from the manifold to cats, mine have rotted and TVR only have 4.5's in stock ! and cant find any anywhere.
Call up I think its Powermaster or PowerFlow Top Gear garage in St Albans, they'll custom cut and weld you some, just take the existing front pipes down to them, and 30 minutes later, you'll have a new stainless set!
Is it the manifolds themselves? My 4.2 ones were cracked so they were replaced with 4.5 manifolds. Apparently they are bigger bore than the 4.2 ones and so are good for power.