The easiest solution would be dropping bomb strike from commandos commander on enemy positions or slightly behind them. Then when opponents regroup to avoid bombs attack from sides. Something similar on smaller scale can be acheived with railway artillery or tornado loiter from other commanders. Its important to coordinate artillery/planes with attack. If other teammates also have some offmap artillery it is good to use them in different parts of enemy forces at once, in many cases opponents will be able to dodge only one of them.
If for some reason you dont want to use commander abilities ukf gives you some of the most powerfull breakthrough weapons. Use churchills for the first wave of attack, they are potent in disabling at guns and mgs and can give you very thick smoke screen. Then, depending on the scale of fight and number of british allies, use comets or crommwell to keep the advantage, kill enemy tanks and drive behing their lines. Never send mediums before heavies, you are going to loose them that way. Always remember to attack one, chosen point in defencive line and attack from as many directions as possible at the same time. The rest is up to micro and coordination with teammates.
Ahh ok. i will try that. thanks