"At the same time...and visited on the same day, St Nunns Well has now got a family of plastic faeries residing around the bowl...should they stay?...I would love to get rid of them but part of me says someone put them there for a reason the same way the ancients would have left offerings."

I suppose the only 'judgement' you can make is damage to site, and presumably the plastic fairies were'nt damaging the site.
Should we make decisions on other peoples beliefs or aesthetic tastes? all very subjective...
I suppose you could remove them under the law of 'ecoside', vandalising the environment of the well. ;).