Hi @NigelP,
It seems that your flow is triggered by PowerApps button.
I made a test on my side, when creating the flow, if I selected a dynamic content accidentally, though I deleted it in the flow, when configuring the button on PowerApps, the accidentally selected dynamic contents are also asking an value.
I am afraid that you will have to delete then recreate the flow without adding a dynamic content accidentally.
Please have a try with it.
Best regards,
Mabel Mao