Regarding the playing football and straying onto other people's plots, I would speak to the allotment people. For the foul language I would speak to the adult in charge of the kids and calmly explain that it is out of order and that I don't expect to hear it even once more in the presence of my children. It is actually a criminal offence to use foul language in a public place - for which the foul language users could be arrested, charged or fined (yes, even the children if they are over 10). I would be tempted to remind them of this should it go on.

Of course, it's a delicate balance between keeping people happy, getting along with people and tolerating other people's differences, but having to 'suffer' bad behaviour and language is not acceptable at all and I certainly wouldn't accept it. I would always appeal to someone's better nature with a quiet chat, but if this fails you do have the law on your side!

Kris