Thanks wce for your input.
I think I'll be returning the STP along with the dozen Purina duck and sweet potato gourmet cat food tins as Fontanelly is already showing signs she's over that flavour cat food!
I'll leave the Laser to be the guinea pig as it has several oils in it's sump already.

Ahh, if only victa had kept producing the thumblatch catcher series, they would be in better shape today!