By Devik Jain (Reuters) -UK shares closed lower on Tuesday, weighed by concerns about a slowdown in global economic growth and a series of negative brokerage actions, while electrical engineering firm Spectris climbed after announcing a unit sale and share buyback. The blue-chip FTSE 100 edged down 0.2%, with spirits maker Diageo, Dove soap maker Unilever and personal goods maker Reckitt Benckiser Group all falling between 2.1% and 1.5%. However, gains in commodity stocks limited the losses. Oil majors BP and Shell were up 0.4% and 1.6%, respectively, after JP Morgan raised its price targets o…