Well It's been a while due to work commitments and a month long trip away in the bus, but I've finally got around to sorting the issue. I could have done with it though, when I was camping in Britain in early July, it was bloomy freezing!
Firstly a massive thank you to all of you who have taken the time to contribute your thoughts here. A couple of you were confirming what I was thinking, in that I needed to make my own section up out of different parts. This was also confirmed by the T4 Wiki, who also advised to go down the personal fabrication route. So yesterday my parcel arrived with some fresh new parts.

The only issue was the silencer was slightly different. I couldn't work out on the website, what the difference was between them all, aside from the price, needless to say I managed to get a different one to the one I had!
Needless to say the difference was not so great as to stop the show. So half an hour later I had a new exhaust made up from the hacksawed off end of the old pipe and the new sections.
Another half an hour under the van and I had it fitted back in place.
I can't say it's made a massive difference, but it seems to be quieter as long as your not immediately next to it, I'm happy I've done it though. There is still a strong smell of Diesel on start up, but it hasn't been used for a long time, so I'm hoping that if I leave it running for a while, everything will be O.K. There used to be a strong smell of Diesel in the van as well, which is why I never used it last year, this seems to be gone as well. I just need to pick a much cooler day then today to properly test it!