Do British universities expect the research PhD applicant to know research methods before they write application proposal?
British universities have recently begun to adopt the MRes (Master's of/by Research) as the preferred pathway for new PhD candidates who may not have a full set of research skills.

This typically involves some taught causes, as well as hand-holding through some preliminary research which may then form the basis of your PhD.

It offers you a couple of advantages: it adds a qualification that you'll have earnt after one year, so  you'll get early rewards. And you can decide after a year whether academic research is for you; and whether or not you can work with that department. If so, you've made progress in your research already. If not, then you can leave amicably with a Master's degree and a new network of academic contacts.

It offers the university an advantage too: it gives an additional point at which the candidate's abilities can be assessed.