https://www.gov.uk/check-uk-visa ... t/somewhere_else/no- ***Warning*** Passengers may make an airside transit if
holding a valid entry visa issued by Australia, Canada, New
Zealand or USA. (SEE NOTE 57398)
NOTE 58969: This applies to nationals of China (People's
Rep.).
NOTE 57398: E-visas or e-residence permits are only
accepted for airside transit when the airline is able to
verify it with the issuing country.
E-visas or e-residence permits are only
accepted for airside transit when the airline is able to
verify it with the issuing country.这条是不给登机牌的原因吧。
要是楼主觉得自己的证件没问题,汇总一下信息,在BA的官网投诉,会有专门的人处理。