That's not great news. I set my tcp port to 0 which says it will make it dynamic. I noticed an immediate increase in speed, but it's still nowhere near what I had before. Before changing the port I was barely able to break 2mbit, changing it to dynamic puts it at just under 5mbit. Before I was able to break 50mbit with ease. You are correct in the assumption that I have no control over the server, but I suppose I can put in a complaint to see if I can make something change…
Thanks for your help cmb, you're a good man.