its took me a good few hours but i have finally found a way.
From Sheffield: Catch a train to Nottingham train station
The do the 2 min walk to the Broadmarsh Bus station to Bay 1
From here the X52 comes ONCE DAILY at 9am
It also stops at - To Alton Towers
9:00 - Broadmarsh Bus Station (Nottingham)
9:10 - Queen's Medical Centre (Nottingham)
9:40 - Derby Full St
9:50 - Kirk Langley
10:05 - Mayfield
10:30 - Alton Towers Resort
Returning: The X52 leaves the park at 5.30 (get there at 5.15 to be safe)
It returns at..
From Alton Towers
17:30 - Alton Towers Resort
17:55 - Mayfield
18:10 - Kirk Langley
18:20 - Derby Full St
18:25 - Derby Railway Station
18:50 - Queen's Medical Centre (Nottingham)
19:00 - Broadmarsh Bus Station (Nottingham)
It runs everyday of the season. Tickets bought on the bus and change given. ALSO IT FIRST COME FIRST SERVED SO GET THERE EARLY! THERE IS NO WAY TO BUY TICKETS BEFOREHAND. ON BUSY DAYS THEY MAY RARELY PROVIDE TWO BUSES.
It leaves from bus bay 1 at the bus station, the first you come to if you are getting there through the underground passage from the Broadmarsh Centre. It leaves Alton Towers from the bus stop just outside the entrance plaza. I would advise getting there at 5:20 at the latest, just in case.
Prices including park tickets (not compatible with any other offer)
Adult - £39
Child - £30 APPROX.
Prices not including park tickets from Nottingham
Adult Return - £12 There is NO OTHER PRICES NOW ITS ALL £12 NO STUDENT/DISABLED FEES.
Child Return - £9
Single tickets are available though the leaflet I have doesn't mention how much they are and I can't remember. I'll check next time I get one and update this post but it's five pound something. Source: Much research and speaking to the transport of alton towers service there number is: 01538 704063
HOPE THIS HELPS.