King Edward, possibly, digesting poem about a crawler (9)

I haven't cracked this one yet — but the brilliant team at Times for the Times have:

TATER (potato, of which the King Edward is a variety) containing A in ODE; a TOADEATER (originally a mountebank’s assistant who would pretend to eat toads [believed to be poisonous]) meant a crawler or servile flatterer; the more familiar ‘toady’ is believed to be derived fron this