I feel a bit the same leofred. I've just been up and down the high street on the census but it is a VERY long high street and there are so few landmarks to narrow down the area where the pub was.
If you have a look at a current map - the google maps satellite is good, I've "narrowed" (
) it down to what streets exist now.
There is Station Road to the north which heads east off High Road. That is on the 1871 census.
Follow that south. Not too far down was the Bull Inn (that looks like it still exists today).
Now along High Road were lots of residences, only a few presumably larger ones were named, such as Chanon Farm and Walton or Watson Lodge. Something to think about too, is that there were far fewer residences and several farms along that road, with quite large distances between residences.
On the 1871, after the Rose and Crown there are a few more residences then William the 4th, then more residences along the High Road, then we come to Bull Lane.
Now I believe that "Bull Lane" is today's "Bell Lane".
(I've followed this road before looking for my own ancstors who lived in Broxbourne.)
On today's map, you can follow Bell Lane west - it turns into Baas Hill, then Broxbournebury (named on the 1871) then White Stubbs Lane, then Broxbourne Common (on the 1871) then Pembridge Lane (also on the 1871). So, this is the enumerators route in the 1871 cenus.
BUT unfortuantely the closest we can get is a guess as to the whereabouts of the Rose and Crown, which is towards the southern end of the High Road before today's Bell Lane.
All of this doesn't help with a photo of the pub, but I think the Herts FHS is worth a try. They may have a photo or drawing of the High Road which includes the pub. You could possibly ask them if there would be a cost involved in the search or if you can give a donation and they may be more inclined to help.
Good luck anyway - let us know how you get on.