tallyho,
I've never had dealings with either of these but you might want to check out Parsons and/or Quality Scope Repairs.
QSR says they deal only with external adjustment scopes:
<http://qualityscoper....com/index.html>
"Quality Scope Repair will only be accepting Unertl, Fecker, Lyman, Litschert, Winchester and other externally adjusting scopes. "
Parsons has been around for a long time:
Parsons Scope Service
Attn Richard Parsons
1563 Compton Road
Cincinnati OH 45231-3433
<http://www.parsonsscopeservice.com/>
Good luck,