By Amanda Cooper LONDON, June 14 (Reuters) – West African crude oil sailing to Asia will reach its highest level in five months this month, in spite of extensive maintenance at Chinese refineries and unfavourable arbitrages, a Reuters survey of traders and shipping data showed on Thursday. Loadings for Asia are expected to rise by 16.7 percent in June to around 2.43 million barrels per day, from May’s 2.085 million bpd. This is the highest since January this year and up a full 22 per