Wow! What do the draft minutes of the meeting say about this? If the minutes record that the decision included the discussion of salary and hours, but members do not believe this to be correct, they should challenge that fact before the minutes are adopted and signed at the next meeeting. If it is not recorded in the minutes, then it wasn't decided. Did you vote on a resolution to appoint the chair plus one to conduct the appraisal of the clerk? Decisions can be changed within six months where necessary, particularly if the decision was invalid for any reason.
Committees and sub-committees may only be established by resolution of the full council and the resolution must include the definition of their powers, membership, public access etc, as laid out in your standing orders. A sub-committee is a committee of a committee, so you can't have a sub-committee without first establishing a committee. With no committees, your whole council must determine the salary and hours of your clerk, so any recommendation you receive from a self-appointed group of councillors has no legal standing whatsoever. Your clerk's contract of employment will define how her salary will be reviewed. In many cases, the clerk will be on a fixed point on the NJC scale, so the annual increment is negotiated by the trade unions and the council simply adopts the agreed figure. In other cases, a clerk may be entitled to progression through an agreed salary band on the NJC scale. It is normal for the clerk's salary review to be conducted on the anniversary of her appointment, rather than a fixed date in the calendar.
You have mentioned several times that the chair and the clerk are good friends. With this in mind, you might wish to discuss whether or not the chair is the best person to conduct the appraisal. An objective viewpoint will best serve the council. Training is available for councillors to equip them with the necessary skills to carry out a proper appraisal. In simple terms, you should have some sort of written work plan (from job description, contract of employment and other sources etc) that sets out the council's expectations, then a formally-defined group should meet with the clerk to discuss the degree to which each aspect has been addressed. Items can be added/deleted by agreement. This gives a clear indication of the clerk's performance. The shortcomings go into next year's plan and the process rolls on. You can't conduct an appraisal without the clerk, but the clerk should not be included in any discussions of her salary. For this reason, the two processes are normally conducted independently and in accordance with your standing orders and financial regulations.
Finally, with all due respect, I think your chair should undertake training in the role of chair, which should be available from your local association. With an annual meeting due to take place in May, you and your fellow councillors might also wish to consider whether the current chair is the best person for the role.