While investigating a problem that some users believed it was related in one of sceneries (it wasn't), we found a problem in one of the airports included in the UK World Update, namely EGPR - Barra Airport.
This scenery use the same GUID b5a61705-97ef-4cc3-a058-4eb7743564cf, which is normally assigned to the "SampleMyBox" from the SDK, to create a custom object named "EGPR_11 Sign"
This results in users that have both the UK World Update and the "SimpleScenery" package from the SDK seeing a big "11" sign on the left side of RWY 14 at MYNN, instead of the big checkered Box from the Sample.
I suggest replacing the GUID at EGPR - Barra, because I'm sure copying it from the SDK sample was an oversight and would confuse lots of users trying to follow the sample.