This is where is becomes tricky to meet all the correct requirements of every city or country so you have to make a decision on what the majority would like or how you feel the majority of places are setup and sometimes it is not always right in everyone's eyes. Doesn't mean it is broken just because it may not match what you are use to seeing. As much as I would like to see this game realistic I know sometimes it is hard to make things perfectly realistic for everyone that plays. I feel that most places are going to have some form of a larger swat truck like an armored truck and I think this is what the game is basing this unit off of. Yes I get that some places have smaller units or use SUV units but you can't make 1 in game unit match the setup of of millions of departments worldwide. If you are a department running trucks like this you are not going to send it out with two units that is a waste of resources. Sometimes you just have to take something for what it is if this is how the game has swat units based (off of an armored truck) then this is how they should run in game if they were based on a smaller swat SUV then I could see the need for change. There are simple rules you have to consider is it broken? or is this really hurting the gameplay? Either way you look at it it will always be wrong in someones eyes you can't please everyone!
I defintely think there should be 2 types of swat unit, and UK players could use both, they would both do the same just one would carry more officers.
Here is a UK and US version of swat truck, SWAT Truck can carry 6 officers like it is now
Here is a UK and US version of a swat SUV, The SUV can carry 2 - 4 SWAT Officers.