In regards of claiming back expenses for Squirrel Street charges, I would think of it in the same way as normal expenses where if you are using Squirrel Street entirely for business purposes or for preparing tax returns, then you should normally be able to claim the charges as per the ATO requirements.

Unfortunately as we are not an accountant we cannot give you an exact response for it, as claiming tax has quite a broad spectrum and best thing to do is to seek for your accountant's assistance to help you on that.