I bought mine from Lloyd. The glue turned out to not be very sticky. For me this was not a problem as I already planned to use a helitape-type protection on the drive side stay and used a smaller wrap of that on the non-drive side to keep the SBDU sticker from peeling off.
This is not strictly speaking a decal it is a very thin foil sticker, I have an envelope full of originals given to me when I visited Ilkeston back in 1986...boring but true.
Always attached in a particular position on the non-driveside stay (I've never seen it originally on the driveside stay) - on the team bikes* it was often in another position entirely.
Thanks again guys, the frameset is with the resprayers at the moment, I believe they are sourcing the Reynolds decals from H Lloyd, so I've asked them to include the oval ones in the order, hopefully I'm not too late. It's good to know that they are available if I end up having to source them myself.