Sounds like you now have to become salesman, not something I enjoy. Over here in the USA it seems large quantity jobs like your boss is after go pretty cheap, unless they are very complex. My first suggestion if you don't already have one is to put up a website. A lot of prospective customers will use that to verify who you are. It can just be as simple as an equipment list and some sample parts you guys have made. I have found quite a few people posing as machine shops on the internet that are doing nothing more than outsourcing jobs to third world countries. Your website will help verify that you are a machine shop and actually do the work in house.