Hi Coghill,
when you say you want to have the fuel tested do you mean that you want an engine that is running the fuel to be put on a dyno or do you mean a chemical analysis of the fuel???
If you want to have the fuel tested in an engine on a dyno then there are a few companies that you might want to conside Lotus Engineering (near Norwich), Ricardo Engineering (Shoreham-on-sea) or Janspeed (Salisbury). If you want the chemical stuff done then I don't really know.
As far as the fuel being 'new' I think that Ricardo done some research on the subject of water/diesel emulsion a few years back, the benefits where said to be a reduction in Nox emissions. The biggest drawback was the tendency of the fuel to degrade (diesel and water separating) after a few weeks standing.
Matt