I know several very good anglers who have never caught a Roach over 2lb from the BA and not for the want of trying. One guy I know spend several weeks in a row after the species resulting in a few near to the 2lb mark but not quite making it.
One venue, very close to where I live happens to contain this very rare species, one shoal I know of contains perhaps 6-8 2lb + roach and two of them more like 3lb!!! These really are monsters, legendary fish that we hear of but are seen once in a lifetime.
Now last season (2010-2011) resulted in 13 roach all over 1lb, these were all caught on a rather suprising choice of bait... Halibut Pellet. This went on from June through to September, after this the Roach on this stretch seem to become invisble, completely dissappearing from sight until the following June. As it happens, this season started for me in July as unfortunatley I had to miss it whilst on Holiday in Florida... I have a hard life don't I ; )
The season started for me on a high, two casts and two wonderful fish. A 7lb 9oz Barbel and 5lb 4oz Chub in consecutive casts on the same Halibut pellet!!!