I think the 503 message is a site performance problem. I thought these were all resolved now but it seems not! I'll talk with our hosting company again and see if there is some sort of problem. In the meantime I suggest trying the upload again at a different time of day. Sorry!
Regarding the booking form - yes you can edit this - go to the admin panel for the site, then Content, then click on Booking Form in the content tree, then click on the form name.
Joe - Voice Admin