BUZZ-Shawbrook: hits over 1-yr high on buyout offer
** Shawbrook up 9.5 pct, highest since Jan. 14, 2016, in heavy volume
** Bank gets formal £842.4 mln ($1.05 bln) buyout offer from private equity firms Pollen Street Capital, BC Partners
** Shawbrook had earlier rejected the same proposal (then valued at £825 mln)
** Stock up about 12 pct this year as of Thursday's close
** Stock by far the top gainer on FTSE 250 in volume approaching 6x the 30-day daily avg after 45 minutes of trade
($1 = 0.8027 pounds) (Reuters messaging:; justin.varghese.thomsonreuters.com@reuters.net)