Technically, an circling approach ends at the MDA, so one cannot use the ILS, but must circle from the LOC approach.
Absolutely not dear G.F. all you have to do is to insert MDA for circling. Once on the ILS the decision to commence circle to land will be take on the MDA for C. to L. procedure.
Eurotraveller, you'll do the same for any IAP. the very much valid MDA is the one for circling approach not for VOR, ILS etc.
Cheerio.
