I honestly think the solution is to treat it the same as doping in other sports. In athletics, all pro athletes must log their location for an hour each day that they're available for drugs testing. Fail to be at location that day three times in a year. Ban.
There should be unannounced calls at...
What about eat sleep ride stables near Eyemouth? They've just relaunched the livery yard so have lots of space and are completely flexible about what can be offered.