Hi Simon,
In spite of the sceptical response to your suggestion, there has been several trials for Lepidiolite in the East side of the Irish Republic.
In fact if my memory serves me correctly, and at my time of life you can never be sure, this deposit was quoted as being the largest in Europe.
A few mining companies have been and presumably are still interested in mining the ore, but how the economics stack up, of working a silicate mineral against the salt deposits, I cannot say.