BUZZ-UK housebuilders: wall of worry

** UK housebuilders take a knock as Liberum issues a relatively bearish note just as valuations retest highs

** Thomson Reuters UK Homebuilding index up more than 20 pct over last 12 mths, within grasp of record

** Barratt Developments (LSE: BDEV.L - news) & Bovis Homes, both downgraded by the broker to "hold" vs "buy", down 2.2 pct & 1.9 pct, respectively. Barratt top loser on the FTSE

** Persimmon (Other OTC: PSMMY - news) , down 1.9 pct & 3rd biggest UK blue-chip decliner, is broker's least preferred in the sector

** Liberum warns sector may have a "wall of worry to climb" with risk on inconclusive UK General Election, margin erosion & prospect of rate rises make rich valuations less palatable

** Recommends investors switch focus in the sector

** Broker's top picks are Berkeley, whose shares have lagged & which Liberum upgrades to "buy" vs "hold", Bellway , which offers volume growth at low risk, & Taylor Wimpey - the best cash returner (RM (LSE: RM.L - news) : tricia.wright1.thomsonreuters.com@reuters.net)