If you can get up a little earlier for your return journey (and don't mind just one change of trains), you can get a cheaper fare than Superbike quotes.
Out 14/03/08 at 1029, arriving 1343 (direct). Advance purchase single fare �26.50.
Return 16/03/08 at 0924, arriving 1515. (Change at Leeds. Arrive 1206. Depart 1240). Advance purchase single fare �36.50.
i.e. cheapest return fare (out 14/03, back 16/03) = �63.00
If you travel out on 15/03/08, both the 1017 service (arrives 1451) and the 1103 service (arrives) offer an advance purchase single far of �17.50. The 1017 service requires a change at Birmingham New Street. (Arrive 1150. Depart 1203). The 1103 train is direct.
i.e. cheapest return fare (out 15/03, back 16/03) = �54.00
Source:
http://www.nationalrail.co.uk/
Chris