Anne Jackson writes

The minimum wage doesn't apply until they reach 21, my grand-daughter
informed me. At 20, her wage is £4.30 an hour...

Your grand daughter is misinformed. From DTI website:

"The minimum wage is a legal right which covers almost all workers above
compulsory school leaving age. There are different minimum wage rates
for different groups of workers as follows:

The main rate for workers aged 22 and over increased on 1 October 2006
to £5.35 an hour from £5.05 an hour.

The development rate for 18-21 year olds increased to £4.45 an hour from
£4.25 an hour

The development rate for 16-17 year old increased to £3.30 an hour from
£3.00 an hour "

It would seem that she is being paid below the minimum wage for her age
group.


--
Kay