I think this is what the grille ought to look like.
Couple of photos including one of your van from 2011 here
link
That was my dads and thats him in the photo. We found it bricked up in a garden in Lincolnshire, and we had to get the wall knocked down in front of it and brought it up on a trailer to middlesbrough in about 1998. We must have done every vintage commerical rally in it for the next five years. Its fully fibreglass. We went back down about six months later to collect a speare engine in his cavalier (a perkins P3, which i think they all are) and on the way back a wheel fell off the trailer and skidded down the motorway in front of us. We just pulled off the motorway and hid.
We had to get in contact with Marley tiles and get permission to use the decals, and they supplied most of them - especially the royal crests on the doors. I made the badge above the grille out of two bits of perspex, some whte paper and some stickon letters from smiths. I also painted the back mudflaps when i was about 17.
Van did a max of 50mph and we kitted the back out with single beds. I slept in it once in a field in Lincoln and it was fecking freezing. The engine cover was made of fibreglass too and was in between the seats (also fireglass), so let in all sorts of curse word fumes while driving it.
He had a green senior van too painted up in British Road Services colours, think it just sold on EBay. (just checked, it did)
I think the most interesting thing we found when my dad was havily into these was the complete lack of spares, information and assistance. these were however the days before the internet really hit off, and we were forced to wander round autojumbles. I remember it took about two years to find the back light rubbers for the senior (Rubberlite 59) but then i guess now it would be a simple google. We went down to Croydon and looked at a few places where they were made, places that stocked bits etc. I remember going to some old guys house who had a senior like my dads (different grille) and he was mental. His garage was like a shrine.