Hi Ben,
If your resting HR is 49 then you are definitely bradycardic as "normal" HR is 60-100. However, athletes and other fit people will often have HR below 60. It is once it drops below 40 that it becomes a real concern, or if you find you are getting regular episodes of dizziness with your current HR.
As for the skipped beats there could be a few explanations. There is a type of rhythm that is irregular called AF, however I don't expect you have that because it sounds like your rate is mostly regular with the odd skipped beat thrown in. Quite likely you are just having the occasional early or late beat. They are quite common, and over a 24hr period 80% of people will have these beats (myself included).
I don't think it's really a worry but if your mum's concerned, maybe next time you visit your GP, request to get an ECG test done just to check what your rhythm is.
If you were getting any symptoms such as noticeable palpitations or dizziness, then I would recommend making an appointment specially with your doc to check it out.