You may find the EMA Webtrak site interesting. You can replay radar information taken from EMA, which fortunately just covers the approach to R15 at BHX. If you replay 25 April from 12.55 you will note SSR code 4177 which crosses the M6 at Castle Vale at 1650 ft (presume asl). The aircraft then disappears as it flies below the radar coverage at EMA.
The next aircraft appears at 12.58 on SSR code 4112 - I believe that this is the Emirates aircraft. Its lowest height recorded shows at 1798 ft, in the Castle Vale area, before it commences a go around to 2500 ft.
As mentioned by EK37, it was surprising to see so many aircraft so far to the left of the approach track, and only being fully lined up at a late stage on the approach. I am five miles out, and I was fairly alarmed to see/hear the Emirates aircraft come straight over my house, rather than in front of it like normal. However, a number of other aircraft did exactly the same.
The Emirates did appear to be lower than 'normal', but I think that the way the approach was flown meant that many people saw the aircraft in a slightly different perspective than normal and this may have created the illusion that he was lower than usual. Certainly the data from Webtrak seems to indicate that he was on the correct descent profile.
Dave
http://ema.webtrak-lochard.com/index2.html