Brits do have tools, you just need to be smarter using them than as USF and SU. Against a single mg42 build, you can ignore it early game as it will cover a very limited part of the map. If it's being carried around as gren support, you'll need to concentrate your forces if you want to engage and figure out how the mg is positioned and try to pull off an old fashioned flank like every faction can. Brit nades are the cheapest teched too. Against a heavy mg42 build, your job is a lot easier as you can get bren carrier and wipe the floor with them as Ost won't have the faust support required for each mg, hell they may have skipped T1 altogether. So as Brits, the first thing to do is determine whether or not he's spamming mgs.
I’m just saying the tools needed to remove simply one MG42 is staggering due to how good it is at holding. In 2v2s the game is just a shit. The problem is the unforgiving insta suppress that makes it damn near impossible to back out of the 'trap' even at the end of the fire arc. By the second or third volley you will likely be pinned and without smoke to block the LOS you'll just have to do a full retreat. This can be difficult early game as you basically lose that squad's ability to early cap. This is particularly hard on USF and brits as USF needs the all the squads it can get for field presences, and UKF simply lacks early cheap units to cap.
I'm by no means saying the MGs shouldn't be punishing and built to hold people back, but the MG42 as it stands can determine the first 7 mins of the game if you must back your first or second squad b/c they simply walked into a pio supported mg42 which can see past its fire arc. The unit easily sets up a possible snowball effect which can roll into mid due to its AP rounds as well as the potency and earliness of the pfaust.