Yes, in principle its a great idea, however, the problem with language learning in this country is the lack of continuety, specialist teachers and time for for it.
Its would be great introducing pre-school children to some regular MFL sessions with fun games and songs etc, but the question is: will this be built on in YR and during the primary years, also with regualr weekly sessions? And are they continuing to study that language through secondary? Very unlikely!
The sad truth is that children may be learning to count and sing a couple of French songs in nursery, in YR they may learn something similar in Spanish, the Y1 teacher may have learned some German at school so she will teach them German ... in Y3 they may do a bit of French counting and asking the name ... you get the idea...
Then in secondary school they start from scratch anyway, not learning one language properly, but they will learn 2! By year 9 students are able to drop MFL which most do because its considered difficult and not important.
So in the bigger scheme of things I think I would want to follow it up, maybe you could also offer your service all the way through primary - there is so much wasted opportunity I feel.
We are a bilingual household (English, German), my DC are bilingual and I thaught DS, 7 a little bit of Spanish. In school they are meant to learn some Spanish, however, the teachers don't seem to speak it and admit to that in front of parents and children. So far (since Sept) there has been no language teaching except a homework (go on website and learn days of the week in Spanish
) - that's it.