Politicians and blind trusts?

I believe some politicians have their investments handled by bankers
using blind trusts. Do senior council officials and senior police
officers also have to have similar arrangements?
I ask because I am curious about some decisions made by my local
council and Suffolk Constabulary.

If these people happened to know the organisation handling their
affairs how would they avoid making a decision involving the
organisation? How could this be checked up by a member of the public?