They're really pretty simple flat L brackets, with elongated slots where they slot under the front bolts of the slam panel, to give you a bit of adjustment. You can find the original fitting instructions as a PDF online here: http://www.sidesteps.co.uk/pdfs/Sidesteps%20UK%20P38%20A-Bar.pdf.
I've just fitted one myself, but opted to make some brackets from 30x3mm stainless bar as the ones that came with it were a bit rusty and bent.