If the objective had been to use the meeting as an excuse to promote the name and face of an M.E.P. who was not elected by the public but who may stand for the next European election, I think you have had some success.
The fact that the signs have remained in position well after the date of the meeting does give some credence to the theory that self-promotion was the objective. From my perspective, that is an abuse.
Your signs refer to Socialists & Democrats. There is not a mention of the Labour Party anywhere. There are so many metaphors that could be used in this situation that there is bound to be a mixture – biting the hand that fed you; trying to pull wool over eyes; fooling some of the people some of the time.
Regardless of which metaphor you prefer, I find your signs very strange and very much less than admirable.