Please ask to confirm this but in general every insurance that is renewed will cancel pro rata - ie with no major penalties but perhaps just a small admin fee. If you go with a new insurance expect to pay heafty penalties on cancellation typically 30% for the first 2 months!!
Check the policy terms but renewing for a year is usually the best bet - put it on direct debit if dosh is tight but you are better off paying it off in one hit.