You can add further representations to your appeal at any time up to the hearing itself..and given that the period between registering an appeal and having it heard could be several months, there's no rush. But IMO make clear at this stage that amongst your grounds will be the council's failure to comply with regulations 6(6) and 7(2) of the relevant Appeals regulations which you submit are serious procedural improprieties and therefore successful grounds of appeal.
IMO, an advantage of giving this detail now is that the council would receive a copy of your grounds and therefore should check their paperwork. Given that the errors are objective, they're there to be read by them. Scenarios:
1. Someone other than the author of the NOR reads the notice, knows their legal a**e from their elbow, recognises that they're on a loser and discontinues now, or
2. As above but they decide to bluff it with the adjudicator, or
3. No-one with the necessary knowledge exists in the chain and they refute your assertion at an appeal.
Maybe there's 4,5,6 or whatever.
But IMO if the authority does not discontinue, then you have grounds for making an application to the adjudicator for a costs award. I didn't detail these conditions earlier, but here they are (ironic as they were omitted from the NOR!):
Para. 13 of Schedule 1 to the 'Appeals' regs provides:
Costs
13.—(1) An adjudicator must not normally make an order awarding costs and expenses.
(2) But, subject to sub-paragraph (3), an adjudicator may make an order awarding costs and expenses—
(a)against a party (including an appellant who has withdrawn an appeal or an enforcement authority which has consented to an appeal being allowed), if the adjudicator considers that—
(i)the party has acted frivolously or vexatiously, or
(ii)the party’s conduct in making, pursuing or resisting an appeal was wholly unreasonable;
(b)against an enforcement authority, where the adjudicator considers that the disputed decision was wholly unreasonable.
(3) An order must not be made against a party unless that party has been given an opportunity to make representations against the making of the order.
(4) An order must require the party against whom it is made to pay to the other party a specified sum in respect of the costs and expenses incurred by that other party in connection with the proceedings.