WHV expiring HELP PLS!!

hi my UK working holiday visa is soon to expire and im wondering how long i must wait until i can re enter UK after leaving as i have some pre arranged social gatherings that can not be changed (after only one month of my leaving uk) would i be able to come back to uk after only a month? i want to stay for 5months for these gatherings (as there are several in this time frame) i tried to contact uk border agency via email and all they did was send me the link to their website which was no use as i tried this before contacting them.
i have seen a few old posts asking similar Q's but no one seemed to answer.. HELP !!