BaileysOnline.com is usually the first place I look for chainsaw P&C kits. A quick glance there tells me they have a 50mm Meteor kit and a 52mm NWP big bore kit.
Note that 044 engine changed over the years, so you need to make sure you are getting the correct parts to rebuild your particular 044. The folks in the chainsaw forum at ArboristSite.com should be able to answer all your questions in detail.