I think England should play Tomkins in the halves rather than FB. Hopefully NZ Warriors move him there sooner rather than later and we see the best of him. Remember when he first broke through he was a stand off, before being moved to accommodate some Aussie signing the following season.
Tomkins was moved to fullback in the 2010 season after Amos Roberts got injured. Deacon and Leuluai were the half backs for the rest of that season.