Hi, I'm pretty ignorant of the different types of modern British paganism so please bare with me. I'm going to write about Neo-Druidsm.
I believe many modern pagans describe themselves as 'Druids' or similar such ideas like 'Bards' etc. I find this odd because Druidism is an Iron Age religion whereby our only solid historical sources comes from classical writers. We know very little about them with any certainty. The only thing we can say for sure is that they were very powerful, apparently being able to stop battles between warring tribes by just their say so.
It is also highly likely that they committed human sacrifice. Remains such as the Lindow Man in Cheshire show evidence of ritual sacrifice and then being deposited in watery areas. Now, I don't pass judgement on these people. They were doing what they thought was best for their children by appeasing the Gods etc. It's also increasingly clear that the 'victims' were compliant with it and appear to have been fed a good diet. I don't class it as murder or anything of the sort. However, knowing what we know today, that the climate influences crops through a variety of factors, not Gods, is it right to look at that religion for guidance? They were good people, but wrong.
'Druids' and other New Age pagans often congregate around stone circles. Avebury, Stonehenge, Castlerigg etc. This is hopelessly wrong, historically. Castlerigg was built ~3,300-3,200BC in the Neolithic. The Bronze Age came afterwards then the Iron Age with Druids in ~800BC. That is 2500 years out of date. We're closer to Caesar's time then Druids were to when the early stone circles were built. That's not to mention the different cultures such as the Bell Beaker culture which came and went between the Neolithic and Iron Age. There was no overall continuation of religion. Yet somehow people following idealistic Victorian ideas about Iron Age Druids continue to base their rituals around stone circles from 2500 years too early. It's the equivalent of us seeing 500bc sacred sites as being Christian churches. We find little to no evidence of activity at Neolithic and Bronze Age Megalithic monuments (stone circles, long barrows, standing stones etc) in the Iron Age.
I'm sorry if you don't follow this Druidism type stuff. I'm just putting this out there for people who do. I've taken the time to learn British Prehistory and many Neo-Druids decide not to learn it and just dance around humming to themselves while professing to be experts in what 'the stones say to us through nature'.