UPDATE 1-Grainger 6-mth property sales climb 42 pct

* Prices achieved around 6.3 pct above Sept. book values

* 42.6 mln stg of new buys completed or in pipeline

(Adds detail)

LONDON, April 13 (Reuters) - Grainger (GRI.L), Britain's biggest quoted residential landlord, is expecting a 42 percent year-on-year increase in property sales in the six months to March 31, as stability returns to the UK housing market.

In a trading update on Tuesday, the company said the completed sales from its core and retirement solutions portfolio were likely to total around 78.5 million pounds ($121.1 million) and a further 30.8 million pounds of transactions were in the pipeline.

The sales have been struck at values around 6.3 percent above September 2009 valuations, Grainger said.

In line with previous announcements, Grainger said it was back in the market for new buys and has completed, exchanged on, or placed in solicitors' hands some 42.6 million pounds of property deals, more than three times the volume of acquisitions for the whole of its last financial year.

(Reporting by Sinead Cruise, editing by Claire Milhench) (See www.reutersrealestate.com for the global service for real estate professionals from Reuters)