What proportion of 16 year olds are paying tax? My guess is <1%.

How many 16 year olds work enough to make above the minimum exemption? (£11,580) My guess is very few. Minimum wage for 16-18 year olds is £4.20/hr, but they'd need to make above £5.56 (11580/40/52) to have to pay income tax as they cannot work more than 40h a week.

I also assume the vast majority have no/negligible assets to earn income off.

So the only tax they would be paying is VAT, which everyone, including tourists, pay and shouldn't confer the right to representation.