I think its a willowherb. The young leaves are a bit broader than the ones that grow on the flowering spikes. Spreads like mad but young ones are shallow rooted and come up quite easily. Trick is to hoe at the first sign. Wish I did that...

Yes its one of the willow herbs. Possibly hairy willowherb Epilobium hirsutum or Epilobium roseum rosy willow herb.

both pull out easily but they do produce a lot of seed if left to flower. I find weeding them out by hand very therapeutic.

Thank you, that’s really helpful.