.. I've now found that this fixes Putty but other stuff doesn't display well, fire up iptraf & it's like Putty was before the UTF-8 tweak.
I have found that if I set the translation to VSCII then iptraf is fine, but Putty is back to being a mess; the line drawing characters work if set to either Unicode or ANSI/OEM for VSCII ot UTF-8, but only in an either/or situation.
Looks like I'll need to post a bug & get the devs to take a look.