They attach with 3 small bolts - you can get at them with a spanner easily enough, whereupon you will find the heads will round off.

The best course of action I have found therefore is to employ the services of a small bolster chisel and hammer to fetch the heads straight off, then brutalise the rusty shield until such time as it becomes detached. Then refit the roadwheels and go have a cuppa.

20K miles of all weather and poor surface driving saw no harm come to my 200SDi after I did this, so I've come to the conclusion that they are not that necessary...to replace them, I am 90% sure the hub has to come off.

 

They attach with 3 small bolts

I am 90% sure the hub has to come off.

Sure does, nothing's easy. Breakers is best bet, mine are shot but interestingly the rear ones like new

 

Might well prove to be the best option, thanks.

 

Last time I looked new ones were no longer available from Rimmers.

 

picked up some nos shields on ebay, havent fitted them yet because i realised you have to strip the hub and the bolts look like a nightmare,
cheers for the chisel/shear them off method didnt think of that, will cut the centre hole in the new ones appropriately to slide them on and drill a small hole in the hub flange to allow new fixing holes to be drilled tapped through the hole