I rode a Lambert as my commuter bike for a couple of years until selling it recently and did replace the death fork at some point. It had a conventional English-thread bottom bracket. Now I'm the proud owner of a Viscount (see http://tinyurl.com/ztr3r). That one had the original cartridge bearing bottom bracket, which badly needed replacing. It was easy to find the press-fit bearings ($5 each at loosescrews.com) and I happened on a ActionTec titanium bottom bracket spindle ($20 on eBay), so for $30 I have a smooth-as-silk bottom bracket that should last for 30 plus years. You can reuse the original spindle, but they're prone to failure at the circlip grooves (see http://bikecult.com/works/parts/bbViscount.html).

Fwiw, I don't think $125 is outrageous for the Lambert if it has a decent wheel set and the cool original crank.

Neal