Comfrey

as I  have been making lots of comfrey tea and using it on my chalky soil.

if you have already been using it, what were the results?  If you have had failures then perhaps there is something in what you have been told, but if not, then I'd say carry on.  Personally I can't see the problem - comfrey tea is likely to be slightly acidic but if you dig in manure, this too would have the same effect.  Maybe someone doesn't like the smell of the tea when its brewing and wants you to stop ....