Additionally, you (or a person with whom you arrive in the UK) must hold:
8) a valid uniform format residence permit issued by an EEA state under Council Regulation (EC) number 1030/2002
You told us that
you are a national of China.
you are coming to UK to Transit.
you are normally and legally living in Spain.
我在官方网站查的。。。。一般是需要签证的
难道楼主运气好?