Sorry, pressed the wrong button - yes about 950ft at 3° from a 50ft screen height. Don't get this with my slide rule!
So far as I'm aware a commercial aircraft should be no higher than the scheduled screen height (50ft or 35 ft usually) over the threshold and no faster than Vref.
Interestingly I've half a dozen books on aircraft performance on the shelf here, and none of them seem to give a definitive definition of threshold (displaced or otherwise). However, taking my Pooleys out I look at page 203 - Dunkeswell, an airfield I've a nodding acquaintance with. That shows a 150m displaced trheshold before Rwy 23 with a stated "pilots must positively identify the displaced threshold to Rwy 23 before committing the aircraft to final approach". The numbers are after that displaced threshold.
G