Do the maths. If you assume a temperature difference across a warm front of about 5º the difference in the freezing levels will be about 2500ft. With a frontal slope of about 1 in 150 the lateral extent will be 150 x 2500 ÷ 6080 = 62 nm. With these figures the rain ice triangle will be from nothing to 2500ft high and up to 62nm wide. Your choices are (a) climb a thousand feet or so or (b) get at least as much icing again as you already have if you turn around. As always, early recognition is important. If you are iced to the stage where you can't climb a thousand feet you are unlikely to be able to turn and fly out.