Ah, Newport, the Land that Time forgot....
At any one time in S and Mid Wales (the S Wales, Dyfed Powis and Gwent areas) the Rozzers have three armed response cars in circulation, but one of those will be so far from the M4 it might as well be on the moon. The other two divvy up Swansea, Cardiff, Newport and the Valleys depending on prospective need - probably both within two miles of Merthyr!
Also, bear in mind that any Rozzer manning an armed response car will not have fired more than fifty rounds of the Queen's ammo in the last year so will be no more skilled than the scrote he's confronting.