David,
You can have all the qualifications in the world, but that does NOT mean you are competent, in your example you can obtain the necessary training and/or qualifications, but this is just the starting point, this has to be backed up by on site experience, with a reasonable level of audited FRA's (or shadowing by a an experienced assessor) before that person can be deemed competent.
And just to make it clear, I am not knocking qualifications, they are a useful tool as part of the proffessional development of the assessor, and the vast majority of competent assessors will have some form of higher level qualifcation e.g MIFireE, NEBOSH Diploma or Degree.
And finally, just remeber you can be a chinless wonder with all the qualifcations in the world, but if you are not competent, then they are just pieces of paper.