Hi Nige,
I must say I was a bit sceptical about these types of veg going into a base sauce. Yet I know for a fact a local BIR put in loads of vegetables into their base as I have seen the pot with different vegetables in it.
Bruce Edwards base sauce uses Carrots, Celery, Green and Red Peppers and is one of the more recommended sauces on this site. I have made it myself and must say it produces curry dishes worthy of comment.
Do give it a try and let us know what you think.
Ray