Market Manipulation? (ATST)

Can anybody throw any light on trading activity of Alliance Trust shares. For some weeks now there have been hundreds of small sell orders bargain size 138 and 110 (obviously uneconomic size for genuine trades). On the other side, there are some purchases clearly working up the share price (narrowing the discount). I can't find any public information on these activities. Best beware trading here until we find out what's going on?