Hi, saw your post and thought to reply as just seen badges on ebay uk.
Unfortunately they're not cheap, around the £70-£100 for mk1 centre grille badge.
There are several companies here in uk that ship to you - search rover spares uk and you'll find a suitable company for you, I know decent cond. 2nd hand are about £50 upwards.
Hope that helps at all
I purchased one of the ebay UK ones last night, I have two, one that is in pretty good condition & one that's a paperweight, but the one that is in good condition has been turned into a wall plaque with some kind of resin/enamel molded to the back side. I was just afraid of damaging it when taking it apart so it might have to stay as a book end.
I'm half tempted to commission a run of them if they aren't readily available.
Tempting. Afaik no one has ever reproduced the series 1 badges. There were two different types too, the early ones had a plastic badge with a stainless surround and steel back/fixings but the later ones were all plastic with the steel fixing glued in.