Yeah my old school MOT chaps told me last year that any missing heat shield is now a FAIL 2020 onwards rather than advisory. So that's exhaust, CAT shields etc.
BUT the MOT man has to KNOW where heat shields are located on every car ...not going to happen with many independents .... but with main dealers ...money for old rope!
CAT heat shields fall off on a regular basis in my own very limited experience of moderns.
So if the exhaust passes under the petrol tank then there might be a shield.
Excel-wise I think we are OK ..can't recall any heat shields on the Excel?