The guidance also briefly considers appeals by rights-holders for orphan works used under EU Directive 2012/28 where the rights-holder and the user cannot agree the level of fair compensation.
Basic information and relevant links can be found on the GOV.UK site here.
There's also some useful information about appeals, which reads like this:
On what grounds can I appeal?
You can appeal on the grounds that the IPO has acted improperly or failed to meet its obligations under the regulations. It is not sufficient that you are unhappy with the IPO’s actions or decision; you must be able to explain why the IPO has acted improperly or failed to meet its obligations under the regulations [that should eliminate most grumbles at the threshold].
Examples of circumstances where the IPO could have acted improperly or failed to meet its obligations under the regulations would include (but are not limited to):
• failure by the IPO to fulfil its obligations to satisfy itself that a reasonable diligent search was carried out; orWhat can I expect the IPO to do?
• failure to put relevant details of the work on the register of orphan works; or
• failure to take into account what types of licence fees are paid for the similar use of equivalent non-orphan works, when setting the licence fee for the use of an orphan work.
You can expect the IPO to abide by any findings the Tribunal may make [Well, yes, that is the very least that an appellant might expect in a civilised society that respects the rule of law -- but is that all? What about a bit of remorse, or compensation? Oh well, maybe not ...].