The United Kingdom has a whole series of approaches to artefact hunting and collecting. England, Scotland, Northern Ireland, the isle of man and the Channel Islands all have different systems for dealing with "Treasure" and Portable Antiquities. There is no reason why Wales has to continue to accept the imposed English model.
In Northern Ireland is a system related to that of the Republic of Ireland, where searching is undertaken legally when the artefact hunter has a permit for that project. This is the sort of system used on the Continent, where any interference with the archaeological record is done with prior authorisation of the relevant bodies which have the power to grant such permits (or refuse them if the proposed project would have a negative effect on the historic heritage). The devolved government of Wales could adopt such a system to curb the unrecorded damage caused to historic sites in the country by unsupervised and irresponsible "metal detectorists". Being caught using a metal detector on a site without a permit would remove any of the ambiguity currently associated with illegal metal detector use which exists in England.
The devolved government of Wales could adopt a solution like that in Scotland. There the definition of "Treasure" is much broader, allowing a much greater variety of archaeological material found by non-archaeologists to enter public collections for the common good. Again reporting of such material is obligatory, with legal sanctions which can be used against those who do not comply or surrender material.
The faults of the English system were starkly revealed last year by the case of the Roman cavalry helmet found at Crosby Garrett, Cumbria which did not fall in the category of "Treasure" and was sold by its treasure hunting finders at Christie's to an anonymous private collector for 2.3 million pounds and is lost to the nation. The Welsh government can avoid such a situation by redefining Treasure together with the principles of rewarding finders.