I'd reply to MOG's post, but I'm not allowed
I think it's a great idea.
What we can do will probably depend on
a) the number of folks who attend,
b) when it is,
c) how much we're willing to pay and
d) how big a favour I can pull
Item d) has been given a significant boost since this news
We do standard days for group bookings, although I'm not sure what they entail or how many people constitute a group (although, again de to the above, I suspect it could be a purely academic issue...
At the very least, I'd guarantee a good look round all the locos and probably a question & answer session on each/all of them
I imagine this'll be a weekend thing (or school hols), so the railway will be open to the public at the time. This has the disadvantage of not having the place to ourselves, but the advantage that it'll cost less / we may warrant getting another loco in steam.
As for dates, here's the weekends to avoid:
(Day out with Thomas)
(Teddy Bears' Picnic)
The Gala could actually be a do-able date, and you'd be guaranteed to see all the locos in steam, but there's the disadvantage that you won't be able to see them for all the people counting their rivets.
Finally, I'd say don't leave it too late in the year; the trip up the line and back is vastly better from an open carriage
than a closed one, but we only tend to run them in the summer as there's a jolly cold wind in them Dales!
So let's get some possible dates mooted, and some potential numbers, and I'll approach the powers that be to see what can be arranged....
 Someone had better bring a video camera so that we can record the answers to the questions of those who couldn't make it!
 Even better from the footplate, but given that firing requires the driver/fireman to pull interesting contortions with even two on board, that's not really a go-er!