Air in ABS System - Help required please

I am on holiday abroad and have left my 620ti with my local garage to carry out some routine maintenance and sort out the spongy brakes problem



The car has new calipers and flexis and a just had a new master cylinder fitted. According to the garage the pedal is a little firmer after replacing the master cylinder but is still far from perfect. They have said that there is air trapped in the ABS unit and a diagnostic computer is required to remove it, the one they have will not do the job.



I am a complete dunce when it comes to braking systems, is what they are telling me correct and what needs doing to solve the problem?



All help gratefully received.

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