I'd have thought you can freeze them shirl' peas are one of the best freezing veg, so surely the pods can't be bad. Just used some rose petals that i froze until i had enough and they came out just fine, so peapods must stand a good chance.
(Do bear in mind that I speak from utter ignorance and take a large pinch of salt along with any advice given.)
anyone remember the pea pod wine in 'The good life'? it got some quite strong responces i see to remember...