I live in London so the selection is not huge and the prices ante crazy expensive.
When you say London, you talking England or Ontario?
that brings me to my second question:
Where are you freeriding? I ask this because freeride does not equal all-mountain.
In general freeride is more off-piste, trees, steeps, variable terrain.
All-mountain is just that, park, on-piste, off-piste.
Generally freeriders tend to like stiffer boots, like the above mentioned Malamutes, the Burton Driver X, etc. But the advice above to try everything on and go with what fits best is probably the best advice.
FWIW, I went from '90s Vans Shaun Palmer Signature Series, to Burton Serows, to Burton Driver Xs (currently on my second pair). I loves me the stiff boots!