Permit to fly microlights can be hired - in fact we have four at Strathaven - as long as they are factory-built. Which ours are, of course, since we use them for training too.
Appreciate you are thinking light aircraft - but then a factory-built C42 or Eurostar is a light aircraft ... one that just happens to be registered as a microlight!
(One of our members has just bought a light aircraft Eurostar and is moving it to the microlight paperwork. Ironically, for an aircraft once based at Prestwick, it will then be banned from Prestwick because it is now a microlight!)
The exceptions for kit-built (micro and light aircraft) are mainly for pilot owners seeking their one hour with an instructor for licence revals.