Five???
I think kids examination is only £125 but still it's going to hurt. With only medicals, translations, photos, police certificate and traveling costs I already exceeded 1000 pounds in spending so if they screw me over and say "Well, sorry Dude but we ran out of visas just yesterday" I will be well pissed off
By the way, I was there half an hour before my appointment and they were OK with me joining the happy bunch in the waiting room. Just filled some extra forms and then off it went. You have different person doing vaccines, x-ray and health check so we were out in less than an hour. With five of you I would expect 1.5 hours max.