Yeah I don't want any restrictions, traffic shaping etc. With our speed of a max 3mb the last thing I need is it slowing down in the evenings, especially as we use iPlayer and YouTube quite a bit.
But the traffic shaping restricts protocols to certain maximum speeds, so being on a slower maximum speed will not make it worse for you, proportionately it will have less effect. I suggest you try it without the Pro addon and, if you then think it would help, add it. My maximum speed is similar to yours and I never noticed any problems from the traffic shaping, on Value or Extra.
Plusnet Extra - soon to be Value Fibre