Fitted a new middle section today and the back joint leaked It's a clamp-type joint and I've reassembled it with a ton of Holts Exhaust sealing paste in it and it seems to have done the trick............so now the f****** front joints' leaking!
Thats a bolted flange joint with a crushable gasket. I'll probably need a new gasket but can anyone recommend a better sealant that the Holts stuff or is that OK?

I've used clear silicone many times and never had a problem with it. Last time I did not even use the high temp one and it has worked perfectly. Certainly easier and seals better than the gum gum type stuff.