It’s interesting to see the swapping of some scrap flows between DBC and GBRf, with DBC also having taken over from GBRF some of the workings into EMR at Liverpool docks. Is this just due to them competing for flows and gaining or losing contracts? Or is there an element of coordination between the two companies, so each can use their resources more efficiently (I’ve no idea if such a thing is even possible)?
It's traffic changing hands when contracts are won or lost (quite often you see press releases coming out saying haulier X has won a contract with company Y for Z years, or has renewed a contract). In this case it's a bit of a scrap swap like you say, with DB picking up flows to Liverpool and GBRF taking over 7Steel traffic to Cardiff Tidal. GBRF already have the contract for shunting at Tidal (plus already work into there with scrap traffic from Beeston - previously Burton - for the Ward terminal at Cardiff Docks).
I don't think there's usually much direct co-operation between companies in terms of hauling each other's flows, although there are some cases where more than one haulier is involved with the same flow (for example GBRF and DB from Portbury to Margam, and DB and Freightliner from Tunstead to Washwood Heath). In those cases if one haulier can't resource a requested train, the other might be able to. This also applies with engineering trains, where there are contracts in place between Network Rail and several different hauliers, but there might be some juggling of services between hauliers depending on resource availability (such as the number of traincrew that sign an unusual route).
Co-operation directly between hauliers can take the form of loco hires (short or long term) and sometimes hire of traincrew to cover gaps at short notice. Another example is DB maintaining the GBRF 60s at Toton (and also hauling them between Doncaster and Toton for exams or repairs). A few years ago DB sub-contracted a few of their flows to DCR (I assume due to crew availability) - resulting in pairs of 56s being seen operating out of Peak Forest, to Attercliffe for example, but I don't think that kind of sub-contracting of the entire haulage element happens very often.
What route would it be using from Laisterdyke?
Last time the Laisterdyke scrap train ran, I think it was split into two portions at Neville Hill. The loaded working ran round at Bradford Interchange and the gradients (and possibly the siding lengths too) meant the train was fairly short. Judging from the most recent photos, the last working was in 2017 (I believe the scrap was destined for Liverpool).
66185 with 9 wagons being loaded in the terminal in April 2017:
https://www.flickr.com/photos/andrewshenton/34237797461/ (Photo: Andrew Shenton)
View of 66194 showing the connection to the main line (due to the layout, the train will have to follow the unit and head towards Bradford Interchange):
https://www.flickr.com/photos/andrewshenton/27790038086/ (Photo: Andrew Shenton)
66185 in Bradford Interchange
https://www.flickr.com/photos/andrewshenton/34237795721/ (Photo: Andrew Shenton)