Which section of the MOT did it fail under?
http://www.motuk.co.uk/manual_360.htm

The only things I can see that might apply:

2.

Check all components for security, condition and operation.

2.

A braking system component:
d.

retaining or locking device missing or insecure.

or

3.

Check all braking system components for any inappropriate repair or modification
3.

A braking system component inappropriately repaired or modified.

They shouldn't fail an MOT though providing they are securely mounted, not corroded

(HEL are stainless so that's not an issue), not twisted or otherwise incorrectly installed or damaged.
