If the Landlord hasn't "ticked" the box one has the right to appeal to have it added.

If there are any such right of appeal - these will be confined to the licensee's or the applicant. My understanding is that any change to a Premises Licence will involve application and payment for a 'variation'. In all truth can we really expect to - see small qualifying venues but who do not now have not Premises Licence permission for non-amplified music - going through the whole process of applying and paying for a variation?      

In so far as I been told ( This information was relayed to a councillor who sits on the licencing committee and took advice from the licencing officer) that one may play and sing between 8am and midnight inside the premises and indeed that is what we do.

Only if the venue has first obtained entertainment permission for this.

Also the Landlord was convinced that the midnight finish was only for instruments not for unaccompanied singing.

Assumptions - they do say - are the mother of all cock-ups. My understanding would be that after midnight the LA could impose any curfew - as long as they first found a valid objection.

However, if one interprets the rules there is enough leeway in the act to allow a decent folk night, I suspect some Landlords simply don't want them.

Sadly it has tended to be how the officers of your local authority interpret the rules. It is my firm belief that even under this new legislation any bold and imaginative local council could provide sensible leeway to enable most of the activities that the words of the legislation threaten. The trick I feel is up to us to make sure that our local authority is bold and imaginative as many licensees and musicians can be - if that is possible.