2008 E70 SD DPF Issue - Help

[SootE70]

Hi, first time poster on the forum, but not first time BMW owner.
I've had the DPF on the X5 properly cleaned as the car kept going into limp mode.
However the soot level rose rapidly again to 60g and the limp mode occurred again.
I have the Bimmertool app that allows me to force DPF regenerations, however the regeneration keeps cancelling and restarting.
So far, I've replaced the thermostat with a genuine one and replaced the fuel filter heater as it kept throwing a code.
The injector readings on four injectors are pretty much zero, with one around 1.3ml/stroke and one -1.3ml/stk.
I need help from anyone who has experienced this same issue.
Many thanks in advance.