You have an MP for one official reason only - to represent you in the House of Commons - in debates, but most importantly in divisions (parliamentary votes).
This is they only thing they have unique privileges/rights to do - this is what they are paid for.
Everything else they do - charity work, community activities, etc it entirely their own business - they could do this whether or not they were an MP. They are not councillors, social workers, community activists - at least not as part of being an MP. Any such activities they do on their own account and should do on their own time at their own expense.
With this in mind - the essential right to vote in the House of Commons - the biggest influence on any non-independent MP is their party whip. The party whip works for the party leader, to force MPs to support the party/party-leader on parliamentary votes.
Any MP who does not absolutely and clearly show which whip they obey is deceiving the voter, and hiding the biggest potential conflict of interest they have chosen to accept.
It should be a legal requirement (if not already, under the trades description act) for all MP's to declare their party loyalty/whip whenever the represent themselves as an MP.