Whether allowable, or not ? The thing is under section 37 any activity carried out in normal course of business and is contributing to revenues and is pertaining to business is allowable. Where you're taking consultation from some outside consultants, in due course of business and paying fees for geographical prospecting/exploration, the amount paid will be allowable.
Now as far as salary is concerned, are you sure you're paying salary to them ? Aren't they on the payroll of the the client , so salary should be payable to them. The classification instead should be reimbursement of expenses, and that should be the head under which you classify these expenses in your company. Essentially, the client is claiming their employee is working for you and in course of consultation/work, the expenses they incur will be payable by you.
That probably should be the classification.