I think that's a slightly unfair comparison. In as much as, Shaw and Lallana both qualify as home grown for european squad purposes, which adds a premium when moving to an English club competing in Europe. Also they are moving between direct league competitors, which also adds a premium, and on top of that Shaw has at least 10, but up to 15, years left in the tank - so there's a premium there too.
One could easily argue that the £31.5 million for Shaw is a bargain compared to £50 million for David Luiz, a defender who can't defend...