The MCA have issued guidance (MGN 389) about radar reflectors. They have clarified their guidance to state that, for small boat operators, you should have the best reflector you can rather than necessarily having one the complies with the ISO standard. A test was carried out on various reflectors and for passive reflectors, the Echomax 230 came out as a good compromise between price and performance.
As charliee has suggested, an active reflector is more effective than passive but it is on the assumption you have power available to it.
__________________
|