LONDON, Oct 22 (Reuters) - British retail sales dropped by 0.2% September, official figures showed on Friday, adding to signs of weakness in the recovery and bucking economists’ expectations in a Reuters poll for a monthly rise of 0.5%. Retail sales volumes in September were 1.3% lower than a year earlier, the Office for National Statistics said, weaker than the poll forecast for a 0.4% dip, although they are still 4.2% higher than in February 2020, before Britain went into lockdown. (Reporting by David Milliken and Andy Bruce)