You absolutely need a holding midfielder or you will get caught out time and again. Using two W(s) with two FB(s) is also not going to produce anything, as WJ said. Strive for balance across the field. One W(a) and one W(s) ideally. I tend to mix up my fullbacks as well with generally a CWB(a) and the other on support, as opposites of that particular side's wingers. Play to your best players' strengths. Finally, as you are a Vanarama team I would recommend keeping things as simple as possible. Simple roles (CM, AM, W) and a straightforward game with few TI's and PI's. Players of that caliber generally aren't very intelligent and can't handle sophisticated tactics.
During a match put the viewing mode on "Comprehensive" or better to see what your players are doing and how your tactics work on the field as opposed to how you think they should work.