(Reuters) -U.S. private equity firm KKR and Assura have agreed on the terms of a "best and final" offer for the British healthcare real estate investor's sale, valuing it at nearly 1.7 billion pounds ($2.29 billion), the companies said on Wednesday.

The latest proposal from KKR and private equity firm Stonepeak Partners of 52.1 pence a share including dividends trumps the 51.7 pence offered by rival suitor Primary Health Properties ( PHPRF ) last month.

Assura joins a growing list of UK companies being bought out and taken private by overseas private equity firms or investment companies, attracted by cheap valuations.

($1 = 0.7415 pounds)