I tried lots of different options, none of which worked, until my lovely husband suggested the coloured base card which turned out to be the answer.
I kept it simple, using a freebie stamp from a magazine & a plain greeting.
Cardstock: Lidl & Coredinations
Stamps: Docrafts Michael Powell The Harbourside MPL907209
Greeting stamp unknown
Inks: Memento Teal Zeal & Morocco