"it was impossible to sit down for five minutes in Hyde Park after seven in the evening without being either accosted or arrested"
Male homosexual couple depicted in January1928 edition of Hentai shiryō.
Public DomainMale homosexual couple depicted in January1928 edition of Hentai shiryō. - Credit: unknown

 Hyde Park was an important cruising area for gay men during the 1930s. Mr. Mybug is presumably suggesting that one could not be in Hyde Park for five minutes before either being accosted  by a homosexual, or arrested for being a homosexual. 

When Cold Comfort Farm was written, homosexual acts were illegal in the United Kingdom, and they remained so until the Sexual Offences Act 1967  decriminalised sexual acts in private between consenting males in England and Wales.

 

Hyde Park
Creative Commons AttributionHyde Park - Credit: siegertmarc