Why would some “experts” think that when Celts were in England they wouldn’t be in Wales too?
[snip] Experts were initially sceptical, since chariot burials have, as mentioned above, not been found in Wales before: there are around 20 such burials across the UK but most are in the North East of England. However, over the summer a preliminary excavation was started by Dyfed Archaeological Trust and National Museum Wales. This was part funded by Cadw, which manages a number of Wales’ historical monuments and buildings. Ground radar showed that the site was much more extensive than previously suspected, possibly even larger than the well-known Iron Age hillfort site of Castle Henllys, also in Pembrokshire. An experimental investigation unearthed the tops of two rusted iron chariot wheels and a pony’s tooth. In some chariot burials, a form of burial reserved for those of wealth and high status, the wheels are flat, but this one was buried standing and a mound erected over the top. [/snip]
https://wildhunt.org/2018/12/new-archaeological-finds-in-uk-shed-light-on-pagan-past.html