School trousers for tall DD

[feetheart]

Not sure if this is the right place for this but the 'Secondary School' topic didn't seem right either!
DD is nearly 13 and wearing Tu age 15 trousers. Noticed today that they are getting short so looked up the next (and final) size but they have stopped doing them in black . So two questions:

1. Anyone know where we can get black jersey school trousers from?
2. What do you do when they have grown out of the high street uniform?

She is only in Year 8 so we have over 3 years to go (thankfully 6th form is no uniform!)

TIA

Anyone?

My twins are 9 and tall, I went to m & s £12.00 a pair, fantastic and you can order them online

My DD (tall, and aged 12 and 15) wear adult trousers from New Look. I did suggest Primark because it's cheaper, but according to DD1 the cut isn't good enough , and even the size 6 fall off DD2.

Next do a tall range