Ignoring the fact that nothing that is not on the agenda can be discussed or agreed (it will have to go to full council at the next meeting), a small allowance for the Chair, whether co-opted or not, is quite common although does need to acknowledge that sometimes the chair incurs expenses that other councillors might not. It is common that this allowance be used for little things like, perhaps, a small gift to a volunteer. £100.00 is hardly a huge amount and it must go through the "expenses" procedure, i.e. funds reclaimed on submission of a receipt, or it becomes income payable through the paye system.