Anglian,
I think it's a contra between various charities and solicitors. Solicitors will do it as a means of getting extra work and identifying extra revenue, I don't think there is any issue of charities being beneficiaries (unless you wanted to anyway). You make a good point though.
Trash, you don't have to see one in March - just get in touch with one. Make up a name and email addy, put in a location a little closer to civilisation and the next time you hit the big lights of Dorset, you might want to drop in on one you've identified? But yes - shame.