I've emailed the company and also written to the head teacher about it. Here's the text of my email, addressed to the person the letter came from. It may be slightly over-pompous, but that's how I was feeling....
----------
Dear Ms X,
Thank you for your letter of 17th March concerning my daughter [name]'s poem, which you say has been chosen for inclusion in a collection 'representing the best of the pupils' work'. I would like to make you aware of one or two points and to raise some questions.
This work was entered by the school without the prior knowledge or consent of parents. Had I been aware of the exact nature of the 'collection' I would not have consented to my daughter's participation.
I am a professional writer, tutor and consultant with 15 years' experience. I have had nine books published by major and leading independent publishers, have had work in several anthologies and am represented by a leading London agent. I have been a member of the Society of Authors since 1994. I am teaching my daughter that the way the industry works is that I provide a service, in return for which I am paid. With this in mind, I would like to establish what rate of advance and/or royalty you anticipate paying my daughter for the use of her work in your collection.
At the start of my career I was published in small press magazines and anthologies who could not afford a royalty because of their being small, non-profit-making enterprises. This is entirely fair and understandable. Contributors were, in this case, rewarded with a complimentary copy or two of the magazine or anthology in which they appeared. If this is the nature of your enterprise, I would be happy for you to clarify this - although the tone and content of your letter lead me to think that you are a profit-making company. It is completely unacceptable to ask contributors (or an adult on their behalf) to pay to see their own work in print - this makes you a borderline 'vanity press', and the kind of organisation which I continually direct my writing students to mistrust.
Increasingly, writers are being expected to work for nothing - with the kudos of publication or publicity itself being presented as some kind of reward in itself, and one which allegedly means that they do not need to be paid. The Society of Authors strongly resists this attitude and encourages writers to insist on a fair fee at all times. You would do well to remember this.
It is, I feel, morally dubious that you are encouraging children to send their work to you to be anthologised and then emotionally blackmailing parents to pay for copies. It is a standard industry practice, endorsed by the Society of Authors' and the Writers' Guild, that all writers (of whatever age) should be given at least one complimentary copy of the work in which their writing appears. If the work is published for a profit (and at an exorbitant £15.99 per copy it cannot be anything but), the writer should expect several complimentary copies.
I do not believe that you are in the business of encouraging young writers at all, but simply that of making money. Furthermore I have seen anthologies produced by Forward Press before, and found them to be extremely shoddily produced with poor-quality paper and blurred ink, and obviously containing every piece of work which they were sent (thus removing any element of competition or editorial quality control).
The copyright form will not be signed unless these concerns are addressed to my satisfaction. In the meantime I will encourage my daughter to direct her energies towards genuine competitions and publications.
Yours sincerely etc.