How much should repointing in lime mortar cost in London?

My Victorian house is currently being renovated, and I would like to have the front and side of the house re-pointed. The top of the front of the house was repointed (I assume by the previous owner) with a cement mix but the lower half of the house which was covered with ivy still has its very crumbled lime mortar pointing. As the house it 100+ years old, I would like it to be re-pointed using lime mortar. My builder has quoted £60 per metre square , and the area to be repointed is roughly 100 metre square.