We built something very similar from what is being discussed above, including scores over time, payments, improvements, etc…
I would say that using all of the big 3 providers (there are other agencies too!) would be extremely expensive for Emma. It could also lead to confusion.
While it is true some providers have more data for some credit account types than others, an overview of 3 scores would likely lead to confusion of the user. The scores are different ranges, have different metrics, and you will never know exactly what makes up a 650 or 800. That’s the CRA’s secret sauce and while it’s clear things will affect the score (electoral roll, missed payments, etc…) they will never tell you how many points that will change your score by.
Therefore it makes better sense to go with 1 provider for now. If you look at companies like TruNarative (we don’t use them however) then you could do a waterfall approach to searching for score.
E.g. search on TransUnion, if thin file (little data) then search on Experian. That will keep costs down while also ensuring someone has the ability to get a score.