Visited the garage this morning. They’ve acknowledged the problem and shown that it was the product at fault. 2 bottles, same packaging, different fluid in each. Their supplier is across the road, so we brought them into the conversation also.
Question: How ****ed is the system? Will just flushing through with copious amounts of correct fluid and replacing the master cylinder again resolve the problem or will it have screwed my ABS module and brake caliper seals.
Pretty much anything rubber that has come into contact with the Dot5 fluid will likely be compromised. Rubber and Dot5 do not like each other.
So any rubber seal in the system, the rubber Flexi hoses, any gaskets or seals made of rubber will likely all start swelling, distorting and possibly leak.
I’ll agree with all that.
Basically a complete reconditioning for the brakes and clutch systems.
As it’s a safety issue now.
All is going to end well and fair. Brake Master Cylinder and ABS pump will be replaced with new second hand parts, all calipers, clutch master and clutch slave and clutch flexi line to be replaced with new. Flexi brake lines are IL Motorsport braided lines (teflon) but they will be removed and flushed and the hard lines will be cleared with compressed air and flushed through.
The garage will then sort it with the supplier once they analyse what was in the bottle.
Just glad we found the root cause of the original failure and its all going to be sorted.
Excellent news, great to hear the garage coming through for you. I hope you get your car back soon 
All sorted. MOT trackday 14th June booked as a shake down on a “safe” circuit.