Obviously they don't distribute equally, as that would be like 0.005 migrant per square in of the UK and you'd need a steam roller for that. Okay yeah we move the migrants away from Kent? Then what they need deporting,okay let's move them all the way back across the country in a massive time waste, or target what ever labour constituency is nearby?
You are suggesting a policy that would target labour constiencies though which is a political nightmare, imagine if any sitting government could target the constiencies of their opposition with what ever they like and leave their own alone. It's such an awful precedent. And what your suggesting would require some sort of policy to enable it.
It would break the UKs politics for good.