A friend of mine is a veggie so, whenever we're out and about together, I have to keep an eye out for veggie restaurants (or non-veggie ones with plenty of veggie options).
'Veggie fish and chips' seems to occur on almost every veggie menu these days, so it's certainly not unusual.
For example it's included on the menu of one of the two veggie pubs in this area:
http://www.vegredlion.co.uk/menu/
The food there is superb but the 'fish and chips' wouldn't be my own choice.