they are if within 12" of the brake servo 
.
.Been looking into this myself.
This is out of the MOT manual-
It is essential that repairs to corroded or damaged areas are properly carried out. This requires that suitable materials of appropriate gauge or thickness are used for repairs. Additionally:
· Any plating or welding extends to a sound part of a load bearing member.
· the repair must appear to be virtually as strong as the original structure with only continuous seam welding being acceptable for patch repairs (even if the patch extends beyond the prescribed area).
· spot welded joints are acceptable where the original panel has been replaced to an existing spot welded flange (provided the original defective panel flange has been removed). Stitch or plug welding is acceptable as an alternative to spot welding in these cases.
· MIG brazing, a combination of adhesive bonding and riveting, or amalgamations of these with other joining methods may be the vehicle manufacturers recommended method of repair. Such repairs must therefore be accepted unless they are clearly inadequate.
Check this site MOT UK car and vehicle MOT information equipment car servicing parts and spares - corrosion
This is out of the MOT manual-
It is essential that repairs to corroded or damaged areas are properly carried out. This requires that suitable materials of appropriate gauge or thickness are used for repairs. Additionally:
· Any plating or welding extends to a sound part of a load bearing member.
· the repair must appear to be virtually as strong as the original structure with only continuous seam welding being acceptable for patch repairs (even if the patch extends beyond the prescribed area).
· spot welded joints are acceptable where the original panel has been replaced to an existing spot welded flange (provided the original defective panel flange has been removed). Stitch or plug welding is acceptable as an alternative to spot welding in these cases.
· MIG brazing, a combination of adhesive bonding and riveting, or amalgamations of these with other joining methods may be the vehicle manufacturers recommended method of repair. Such repairs must therefore be accepted unless they are clearly inadequate.
Check this site MOT UK car and vehicle MOT information equipment car servicing parts and spares - corrosion
The V8 man
Well-Known Member
They are definately part of the mot ive just had mine done, had to repair both sides as brake servo on one side and slave cylinder on the other side, and like Mad said as long as the rot is within 30cm of either its needs fixing, there are repair panels available.
