Ok, solved this problem by visiting roland U.S. site as the help offered in this country is useless. The instructions given by email would not have worked even after the update was installed. Luckily, there are instructions that come with the download. If you have same problem as me go to http://www.rolandus.com/products/productdetails.php?ProductId=772&tab=downloads&skip=true
and update the opperating system on the RC-50 to RC-50 System Update Version 1.01
Then hold loop sync and phrase 2 button (think it was phrase 2) to change it to sound priority mode. Then it will play back correctly what you recorded on the first loop, rather than missing the first beat.
Am v.happy I have found this, as after much searching I can't find any other loopers out there that offer 3 seperate loop tracks and the ability to switch between them effectively. Plus, it's a very convenient size, better than a load of rackmounted stuff to haul around.
When hitting the reverse switch ( I assigned both external footswitch and the onboard Tempo pedal to reverse) the change is not instanteaneous. There is a second or so delay before it plays in reverse. Not a problem for most, I suppose, but I have a piece that switches rythmicaly between playing forward and reverse which means hitting a pedal in time and reverse/forwards changing immediately. I think they could do with another software update to solve this. Now I have to keep room in my enormous pedal board for the old rc-20, as that does the reverse as it should - when you hit the flippin switch!