Jeff
It's possible to certify the aircraft if it meets the stringent requirements of EASA certification (The R66 still doesn't meet EASA certification requirments). This palying field is level.
However, as an 'Experimental' it won't meet those requirements in several areas. In order to allow a lesser airworthiness standard for 'Experimentals', individual states can specify their own requirements (BCARs in the UK) but this restricts the use of the aircraft to the state of registry (unless specifically apporved otherwise by other states). Other EASA states have less stringent requirements than the UK (Italy is an example), then there are other states that have more stringent rules.
A certified aircraft conveys a 'right' to fly. Any other system such as 'Experimental' or 'Permit to Fly' conveys only a restricted 'priviledge'.
JJ