I need to stock up on blast media and am about to place an order for JBlast Supafine and JBlast Fine. As it gets delivered on a pallet the shipping costs are the same for 100kg or 1000kg so if anyone in the South East needs some let me know in the next day or so and I can add you to my order.
Both are Iron Silicate Slag and fairly well known for blasting.
I use Supafine for chassis cleaning and seams - works well in your typical 20gallon blast pot with a 3mm nozzle. (don't tend to use it for stripping full panels as it can put a fair bit of heat into the panel if your not carefull)
JBlast Fine I use in my blast cabinet as it is a little courser and the nozzle can cope with the bigger particles.
If I get the bigger cabinet I am after I might be putting in an order for soda which I use on the engines etc so if you are interested in that let me know as well.
The JBlast I reckon will work out about £9 per 25kg collected from Folkestone. Not much in it for me but i know its a right pain trying to find a local supplier and the e-bay crowd charge £9-£10/bag plus £5 postage
so thought this might help any locals out that have a blast cabinet or such like 
Cheers,
MM