A parish meeting is an meeting of electors and does not have to be convened by the parish council but nor are any resolutions of the parish meeting binding on the parish council. So, you can convene the meeting yourself.
A complaint about the conduct of a councillor should be directed to the local monitoring officer (usually an officer of your district, borough or unitary authority). The parish council has no authority to hear or deal with complaints about member councillors after the Ledbury case. Frankly, also following the Ledbury case, there is very little a monitoring officer can do other than suggest retraining.
If you have a complaint about the way in which your council as a whole operates, you could raise this with the auditors. Your parish council should publish the contact details of the external auditors and they have the power to investigate financial irregularities (which might include conduct if decisions are not taken in accordance with appropriate procedures).
The fact that there were insufficient candidates for a contested election at the last election is not relevant as all would have been deemed to be elected. Parish councillors are elected for a period of four years and many will be required to retire next May and offer themselves for re-election if they wish. The ultimate sanction is to ensure they are not re-elected by offering more candidates for a contested vote so they can, in effect, be voted out. Check with your district council's elections office to see when your next full council elections are being held.
