Nice looking syrup c0ps. You can do a test tonight if you like. Put one of those bottles in the freezer and if the syrup freezes hard then it's too thin. If it ends up more like roof tar then it is the proper brix or even heavier. If it's the latter, you might just want to leave them be. It might save you the trip tomorrow and you can pick up a replacement hydrometer when you aren't having to make a special trip. You can also order one online from Home Hardware and have it sent to the Bolton store.