Ok you guys have now got me rethinking.
Can I ask then ....
De it really matter what I do at my end if the same is not done inward bound for example if I prioritise certain traffic (x box) will my router give it a priority going out but not coming in?
Yes it does. Prioritizing outgoing traffic will affect incoming traffic due to the syn-ack handshake
I think also I'll just manual load balance by routing upstairs traffic down one line and downstairs traffic down the other and then set policies to fail over
that's an easy way but not as good as proper per-packet load balancing
Thanks again for your replies. Is there a better way to get the max benefit of a couple of lines so that game traffic and iplayer traffic do not affect each other?
You could use QOS to achieve this, or FQ-codel