Grange Hill at Elstree Studios

I watched Grange Hill regularly in the 90s (1994-1996 being my favourite era) up until 1998 and I also saw all of the Sunday morning re-runs. I have always been interested in Grange Hill's history and filming locations and I always think of Grange Hill when I see Neptune House in Holby City. Something I always thought was odd was how after 1990 the front of Neptune House was never seen in Grange Hill again (with one brief exception in 1996).

I know they built a new set at the back of Neptune House, but this appeared to be a new building in the series and the front of Neptune House wasn't used as the school entrance again - all we ever saw was the back of Neptune House from 1990 onwards (in all honesty the back of the building didn't resemble a school building). It just seems odd to me that after 1990 all exterior filming at Elstree was confined to the "playground" (in reality a car back at the back of Neptune House) and the purpose built exterior set.

Does anyone else think that the outdoor set at Elstree looked a bit fake?

Should add that Grange Hill was shot at the BBC's Elstree site (usually using an OB truck), not 'Elstree Studios' - which is a separate location and operation.

Sorry, I meant BBC Elstree, not Elstree Film Studios.