To give you an update;
It seems that public transport would work out cheaper or the same as the coach. If you have not yet made travel arrangements for Nottingham you could consider these easy
options if your not driving or sharing a lift.
1) An advance train ticket from London St Pancras to Nottingham - from £18 return if booked online an national rail website in advance (http://ojp.nationalrail.co.uk/service/planjourney/search)
2) Coach from London Victoria - £15-20 return depending on time of your journey (National Express website - http://www.nationalexpress.com/home.aspx)
The Depot are trying to secure further parking for us and as it's on a Sunday street parking is also an option along with the NCP type places around the area.
Look forward to seeing you in Nottingham!