Hi @Isabela, thank you for the advice and the video.
I have bought a set of flanges that hopefully will fit my pump. They come in all sizes so I should be able to find one that fits me and, if the nipples ever grow (as I kind of hope), the larger ones will come in handy later.
This is the set I bought:
https://www.amazon.co.uk/dp/B0CMPBBHMZ?ref=ppx_yo2ov_dt_b_product_details&th=1

Also, and I know this is naughty, I wanted to get something to stimulate my nipples without suction but for a longer time. Possibly something that I could wear in a bra while doing work. I found this cheap toy and I bought it just for fun
https://www.amazon.co.uk/dp/B0CFV5FQ67?ref=ppx_yo2ov_dt_b_product_details&th=1

Both items should arrive on Tuesday (in 2 days) and I am quite thrilled to give them both a go.