Measuring it - it seems a strange size - approx 730mm. I see standard sizes are 700 and 760.
However, I see that you can buy 30mm extension bits so I'm wondering if this is whats been done (there is a plastic bit against the wall before the door starts).
In terms of tray, the door/wall runs right to the edge but it looks like possibly the dray has been dug into the wall a little (thats Barratt for you so it could be a 760mm tray (its deffo bigger than 700).
Does this sound about right?
Unfortuantely, due to size of bathroom we're a little stuck with anything much bigger?