I forgot I posted this question till I seen my pup lie in it today. Although I didn't think she'd die - your right 14+ he really doesn't like my dogs so of course he wouldn't think of the chemicals
I've sent him a registered letter and asked if either he could removed it or put a little fence around the areas
I'm not concerned if he thinks I'm over reacting, I don't feel I should have to surpervise/scold her when she's relaxing in her own yard.
Thanks for your replies.