Re: Anyone applying (or have applied) @ the Canada Embassy in London
One of my friend applied in Canadian embassy in London for student visa of Canada. He got rejected and received his decision within 4 weeks. Unfortunately he didnt attached SOP which resulted in rejection. VO showed her refusal points based on the doubts which should be discussed in the SOP. Anyway, he didnt applied again because his visa was near to expire. One thing more, there is no appeal rights in Canadian embassy in London, only to submit new application with new fee justifying your previous attempt.
It doesnt matter on which status you are in UK, it must be legal and you should be able to demonstrate your progress in UK depending on your visa categories. For example, if you are on PSW then your previous education and working, If you are student then previous education only.
I am also on PSW in UK and sent my documents to Uni of Regina, Canada. Still waiting for admission which might take 2-3 months.