Later on in the day I did send them another email once I had calmed down with these pictures above and apologising for maybe coming over as angry on the phone.
My response:
"Following on from our earlier telephone conversation which we discussed your disappointment, where we offered you the option of returning the bat to ourselves. We shall carry out further work to the face and edges (at no extra charge to you, to show good will) to make the face and edges one colour but we will not do any further work to the back of bat which will remain the oxidized colour that it is at the present time. We shall also apply one front transfer and one edge transfer to each side before sending your bat back to you as offered earlier."
However, that's pretty much what they said that they would do on the phone and they seemed to have dodged my main issue about postage.
I think I shall send another message back to try and sort something out with them, as I for what's happened I now expect a full bat refurb from the work that they have done. (Why won't they do any further work on the back of the bat?)