I'm in a similar situation—four years graduated, and I only had two poetry professors in my undergrad, one my final year and one my first. I've already been trying to connect with my most previous poetry prof, but he's super aloof. I'm gonna visit his office hours as a last-ditch effort and hope I'm not annoying him. I just sent an email to my first one, too.
I do think that (in general) professors can be difficult to get a hold of and that (in general) they enjoy hearing from former students. I've heard some say they consider writing recommendations solidly a part of their job. So even though it's been a number of years, I would reach out to some former professors you feel understood your work, because you never know! Definitely mention in the email that you're game to have a conversation about how your work has developed, how their instruction helped you, etc. so they can refresh their memory on you and your writing.
Apart from that, I'd also love to more advice đź‘€ I think Leeannitha shared some good tactics that I may try myself!
ETA: I got my degree in the US, so I'm not sure exactly how different it is from the UK in terms of prof/student relations, but I'll also say I feel like I'm particularly bad at forging mentorships with people and keeping in touch, so maybe that evens things out