Comment by ben_w

I definitely phrased my comment badly; but to your point, it depends on the era. Here's the House of Commons estimate in 2002, I don't know how different it would have been in 2000: https://publications.parliament.uk/pa/cm200102/cmselect/cmni...

(Table 1): RIRA Estimated running costs (per year) "£500,00", Estimated fundraising capacity (per year) "£5 million".

I'm assuming that's a typo missing a zero (i.e. should be half a million), not a typo substituting comma for decimal (i.e. five hundred quid). Even with 24 years of inflation, that spend does not suggest a big group to me.