Beware JAR-FCL2!!!
At present a single TR requires a min of 5 hrs, a twin is 8 hrs! Currently, there are no exemptions, but the CAA are pursuing a return to the "trg to CFIs discretion" situation that used to exist pre-JAR-FCL2. The CAA expects a change in the policy in the next few weeks, as soon as the next JAA meeting takes place.
Despite what you might think, the CAA are apparently very keen to see things change.