You need to back check all your old designs including the forces you have ommitted. Some may be ok, some overstressed ( but still ok) and some (hopefully not many) grossly overstressed and dangerous. If the latter then under your duty of care you will have to inform the owners of the structures accordingly and you will in all probability be held financially responsible for the costs of remedial repairs etc.

However, in those circumstances you must take legal advice and advice from your Professional Indemnity insurers before committing yourself in writing. Your PI insurers may prefer to engage another structural engineer to see if he can prove your designs rather than paying out for repairs.

All credit to you for admitting your mistake and asking the question - may people would just keep quiet and moved on.

If your design analyses were based on FIXED bases at your columns, you indeed have a problem.  The fixed base must be assumed rigidly attached to the foundation and there will be compression in the base plate on one side of the column and tension in the anchor bolts on the other side. In addition, there would be lateral shear through the bolts as well.

If you assumed the bases to be pinned, and there were X braces or other braces attached to the column, you don't have the moments at the column bases, but you still have lateral shear and/or tension in the bolts.

If the columns are simply supporting gravity loads, you probably don't have a serious problem.

The British standards most likely have design provisions for anchor bolts in tension plus shear as well as some procedures for base plate stress calculations.

Finally, I agree with MikeTheBike in that you need to return to the designs and ensure public safety/welfare.