It's £36 from chemists (some GPs do it for about £24)
As a nurse and a former Midwife, I very much doubt they will supply you with LT if you say you're breastfeeding. It takes a lot of calories from your body, and you need a good mixed diet to produce good quality milk.
(this is just my opinion, please check with the Doctor or Pharmacist)
Good luck Hunni. xx