I posted this on my local mumsnet, but don't hold out much hope because it seems to get very few posts...
Anyway, this is my OP:
'I have an 11 year old son [ASD, LD, ADHD] and I found it very frustrating over the summer that so many children's activities on offer [libraries, arts, museums, etc] were totally unsuitable/innappropriate for a lot of disabled kids.
I've had enough! I pay taxes [admittedly, not much because I'm poor] for local kids to access a range of fantastic activities, and quite rightly so...but where do those with multiple and complex needs fit in?
Is there anything out there?
Have you found an activity where your child's needs are met?
Any horror stories? [I could tell you a few...]
Fancy doing something about it?' 
I'm harking back to a really funny thread on here at the start of the holidays - totally unsuitable places you've taken/would take dc's to [wish I could remember the ref. It was the start of me loving mn]
But the serious side is that actually, there really is fuck all mainstream, 'in the community' events where my son can take part and be welcomed!
I'm in the North East - but would be really interested in hearing about good [and bad] experiences all over.
I rather like the idea of a 'mystery shopper' -type approach. Anyone up for it?
[I do hope so. I'm sick of local bigwigs patting themselves on the back for thinking they're being so successfully inclusive GRRRR!]