Recompense for the landowner/tenant and discoverer(s) is the current market value as determined by the 'Treasure Valuation Committee' which will also determine share amounts to the various parties. If the 'treasure' does not interest any museum, it is returned to the interested parties for their own disposition.
FYI: For a discovery to be subject to the UK Treasure Act, one of the following must be true;
1) "All coins from the same find, if it consists of two or more coins, and as long as they are at least 300 years old when found. If they contain less than 10% gold or silver there must be at least 10 in the find for it to qualify."
2. "Two or more prehistoric base metal objects in association with one another"
3. "Any individual (non-coin) find that is at least 300 years old and contains at least 10% gold or silver."
4. "Associated finds: any object of any material found in the same place as (or which had previously been together with) another object which is deemed treasure."
5. "Objects substantially made from gold or silver but are less than 300 years old, that have been deliberately hidden with the intention of recovery and whose owners or heirs are unknown."
As a casual observer, I believe that the Treasure Act has worked pretty well, preserving the interests of the discoverer and the landowner, along with the historical value of the find. Some claim that these hoards would bring more on an open (black) market, but I don’t think so. The valuations seem to be about right, although certainly exceptions exist.