The sticks have been discontinued. Amber House, the current brand owners, have confirmed this to me. Not many tallow based sticks around any more.
"Thanks for your recent email regarding our shave stick.
Unfortunately the shave stick has recently been discontinued, so I'm afraid the stock in stores is soon to be depleted. One of the major soap manufacturers in the UK went into administration before Christmas and a lot of companies are struggling to resource their soaps. We have come to the decision that due to the substantial increase in the price of production, and therefore the price our customers would have to pay (over 3x more), that we would discontinue the shave stick with much sadness.
This was our best seller in Erasmic, so it's a shame to have to see it go and the decision did not come easily,
Thanks again for contacting us, and perhaps you would find our Shave Soap Bowl or Lather Shave Cream to be a suitable replacement in its absence."