someone needs to confirm if the FB/prospread service is real DMA. I have started noting lately that if I join the bid and say there were x lots on the bid, my order is not filled even after x lots have traded at the bid level (I have checked that with exchange time and sales). Also I checked that if I join the bid/offer, it is not reflected in the exchange order book which one can check from some other broker feed or exchange terminal. This can be easily tested by joining bid/offer for an illiquid market at quiet time.
This seems to indicated that the orders are not actually DMA and instead internalised. That would make them no different from any other spread betting company.
can someone confirm my impression by testing on your platform/system.