Seemed to kick off about 2.20pm with a cluster of a few big trades at 5 - 5.1c and then snowballed from there. Looks to me like someone wanting to lower their average. Could see it sold down further tomorrow but it look like we might have reached their 4 - 4.2c buy back in price, which could relieve some pressure.
Like I said, Covata can make your head spin sometimes!