what are these?

[XJ40-MARK]

hi guys.
my m8 popped down earlier in his XJR 3.2 (M REG), the car in fact, i was going to buy. anyway, standing and chatting about the car, we wondered something. what the hell are these and what are for;

[kamilb1998]

Covering rust/rot?

[xj12-rob]

My guess is that this the leading edge of the rear wheel arch, if so kamib has it bang on, 300 rear arches fall apart like 40 bulkheads, no wait, worse than 40 bulkheads, this looks like an attempt to cover up rust, or at best to stop it getting any worse, whichever, by now there will be rust in behind whatever this is that has been stuck on, is it matal or plastic that has been added ??

[XJ40-MARK]

thanks rob. i never thought to check what they appeared to be made of, but here`s the strange bit. i got the impression they should be there, for what ever reason, because their on the other side of the car as well. they look exactly the same, in exeactly the same position
we could`nt figure whether it was a cosmetic thing or something to do with the rear mudflaps. dont know. their bloody horrible what ever they are!!
so you guys think their covering rot then?
opps, that`ll please him

[xj12-rob]

break it to him gently!!