(ShareCast News) - Martin Lamb and Gary Bullard have purchased a handful of shares in Rotork, in a bid to stem the falling value of the company.JPMorgan Cazenove downgraded the stock to 'neutral' from 'overweight' and slashed its price target to 180p from 245p. It followed the company's profit warning last week.Both Lamb and Bullard have bought 50,000 and 10,000 respectively at the premium price of 187.84p per share.However it wasn't enough to completely stem the flow - at 1604 BST it had slid down to 175.50p.The chariman and non-executive director will be hoping to turn things around before the company's next trading statement in November.Meanwhile Roger Mather has been offloading stock in Mulberry Group again.It's the third sale he's made in the last seven days, dumping a total of 56,500 shares and taking home a tidy sum of just over half a million pounds.This leaves him with only 83,383 shares left in the company, along with just under 100,000 unvested options. Top Director BuysRotork (ROR)Director name: Mr Martin LambAmount purchased: 50,000 @ 187.84pValue: £93,920 Rotork (ROR)Director name: Mr Gary BullardAmount purchased: 10,000 @ 187.47pValue: £18,747 City of London Inv Trust (CTY)Director name: Mrs Samantha WrenAmount purchased: 4,000 @ 375.60pValue: £15,024 Top Director SellsMulberry Group (MUL)Director name: Mr Roger T MatherAmount sold: 23,500 @ 895.00pValue: £210,325