I intend to grind away the rust on the arches and treat it but not being particularly good with the filler and not wanting to spend a great deal getting a garage to sort it I was thinking of some bolt on arches, the kind you you can pick up peanuts for golfs.

Anyone have know of any (reasonable) ones made for 323s or for other cars that will fit on? It'll probably look a bit poo but I'd rather sort it than leave it fester!

spend time with the filler, cheaper than bolt on's, and it'll look better

Will have to match up the paint as well though, something I won't be very good at!

just get the paint code and mix to that and paint the full panels its better that way

yep. paint the rear arch, all the way up and over the doors, down to the front wing

if you have a colour difference, mix 50:50 base and clear, and paint a foot or so along the rear door, then mix again with clear, and paint a bit further, this will blend the colours in, and the difference in shade will be a lot less evident than doing a panel to panel change

Hmmmm, as tempting as it is to try, starts defeating the budget perspective to repaint such a large amount of car for such a small fix. Also everything has to be done on the driveway next to neighbours cars, don't have enough dust sheets!

I'll have a play on photoshop when I get a chance and see how it would look just black around the flare and on the sill