China tourist visa for British citizens in Malaysia

I can't sure you can get a tourist visa from Malaysia. According to the rule, an applicant holding a passport other than Malaysian passport should provide the original and a copy of his or her permanent residence or work permit which should be valid for at least 6 months and a copy of the passport first page (except for those who are visa or permit exempt for residing or working in the Malaysia). If there is any special request, you will be informed during submission.

You just go to Malaysia for holidays, you can't provide the long-term Malaysian visa or residence permit.