Very successful title and now with the recent movie incarnations there's renewed interest.
The free gift Action Transfers sheet with issue #1 adds about £20 to the value. There's also a poster attached inside which is often missing. A #1 with no transfers sold for £24.06 on eBay UK back in Jan 2008. A set missing three late issues sold for £199 on eBay UK back in Apr 2008. The final issue #332 is a tough one to find (The Final Cut). #5 has free gift bound-in Calendar Poster which is often missing.
A set of #1-332 sold on eBay UK for £173.99 back in Jun 2011.
Note: some PR issues may have no value. Selected issues in FN, VF or VF/NM may not exist in some titles.