OK so it turns out my issue is the same also! Indy has confirmed that the problem is the ABS module and can be sorted with a "ABS Block" which he described as the mechanical side of the module, not the electronic side.
So I spoke to Sandals in Huddersfield and JCT600 in Bradford and both are quoting 185 for the part. Indy wants 100 for labor.
The one thing I don't understand is whats the difference between those who have the DTC light (Triangle with arrow) and the Handbrake light and those who just have the DTC light? (I just have the DTC light, not the handbrake light)
And am I right in thinking that this Hydro repair kit is just a straight swap out? I don't understand how you can swap the module with this? It must be an extra thing they put in the car then??
e90 320d SE Auto, Sparkling Graphite