I am a lab technician (microbiology & molecular biology) and biology student, and I am currently seeking for job in some institutes in the UK. After sending my CVs to the HR departments, I usually got some replies with acknowledgement, or pointing to the institute's vacancies webpage, etc. Now I would like to be more proactive, and I feel like it would be good to visit some labs in person, meet the group leaders and other researchers, learn more about their research, and see how I could fit in these groups with my expertise. I expect this to be more efficient than sending CVs to the HR, as team leaders could know about me, and consider more seriously to hire me in their labs.
My questions are, is this kind of visit possible at all? How much I need to organise it, can it be kind of spontaneous? I know there are some other institutes elsewhere, where it is accepted, and they are happy if somebody just pops in to the lab to meet people and learn more about their work. Might this attitude be general? I am afraid they will find me intrusive. And how I should organise a visit, should I write to HR, or to the team leaders, or just drop in, say hello, telling that I can return later if the time is not appropriate?