DDK - Die Deutschen Klassiker

I almost have given up driving my car because there is an annoying fluffing from the exhaust, I've had it at Revival Cars and its come back as bad as it went in and I am sick of throwing money at it.

Basically it has standard heat exchangers and a twin exit pea shooter Turbo Thomas in stainless. The heat exchangers were changed at Revival.

It seems to be worse inside the car than out and I can't find the leak.

Is there any clues as to what I could do to trace the escape ? I have tried two hands over the exhaust tips and it can be hear less, but not as bad. It obviously is an old car and the engines in these are never quiet so its hard to hear where and its also very bloody hot dow there !!!

I don't know if I'm being particularly pedantic about the sound of my car and I should just get over it, is this common, or is there something anyone could recommend, I am ready to sell the car its driving me so nuts......

Could you describe the fluffing noise for us ?

Its either the joints between the heat exchanger and the TT exhaust or the manifold to cylinder joint on the heat exchangers.
The best thing to do is take it off and check the joints and mating faces as there will be witness marks if it is leaking from there.
I have a TT exhaust on mine the same as yours and have no issues at all other than people complaining that its a little loud! but I did go for the full system with the J tubes and basically cut the old J pipes out of heat exchangers and replaces with the new TT stainless steel J tubes.
Check the flange faces for flatness with a straight edge. They can be filed flat if they are not to bad, and a double exhaust gasket helps.

Could it be a loose piece inside the exhaust?

For testing, use two rags instead of two hands, or better smoke test it/vape it, this will help you pin point the leak. There are a couple of other ways to do it, this is done with the engine off. Basically block one of the exhaust exits and blow smoke in through the other. It will come out of the heads/inlet as the exhaust valves will be open on some of the cylinders, so try that as a first idea; But if you really need to, pull out the spark plugs, turn the crank so only the inlets are open on that cylinder (i.e suck stroke), then blow up one of the exits on the exhaust, and do it cylinder by cylinder, this will reduce the amount coming out of the inlet/heads and the exhaust valves will be shut on less cylinders, but will take more time. Another alternative, is blow compressed air in (low pressure), and leak test with leak detector spray and or do it with a vacuum cleaner (suck and leak test). There are lots of ways you can do it. Same goes for solving air leak issues on the inlet side rather than exhaust

If you pop the rockers off, all the valves will be shut and you can blow smoke up the tail pipe (or lightly compressed air )

Did Max check for any loose head studs? That might be a good idea, if not. Or a leak down test, just to be sure.