it's only really known by BP Shell Vitol Mercuria Addax Statoil and the players which have physical bbls in the region, and also active trading desks.... and their Brokers! For example a lot of Fortis crude, which sets the brent contract as it is the lowest of the BFOE grades, is held offshore in floting storage on VLCCs. Likewise GO is very dependent on the water level in the Rhine and how much they can actually get into and out of central german refineries and storage. You can only get a feel for them if you are active in them bloomberg and reuters publish the occasional story on them (to be taken with a pinch of salt) but no regular data. I think your best bet is to get a hold of a broker very active in gasoil futures, not someone who can just broke them, but someone who has considerable flow, though they will only give you the data if you're willing to execute through them every now and then!
Thanks Henry. Interesting stuff about water levels in the Rhine affecting GO storage levels. I figured the only source of this info was brokers. PJK International publish inventory data - presumably only for their clients. I don't think I'd do enough business to interest them.
will your clearer let you take ICE gasoil futures on? I know someone who would probably be willing to share so long as you do the odd bit with them. Drop me an IM!