Thank you all. After a few days and 10 hubs my experience is as follows:
1. My score fell quickly as I added eight articles in one go. This meant that all 8 started with a score of 50 and since I was a new hubber this led to my Author score to fall to around 23 which is why I was so jumpy about things.
2. I then read a hub about not adding any more than 3 hubs in one day as the lower score will dilute down your author score. Seems that’s what happened to me.
3. Day 2 I added three articles and steadily my articles are scoring higher, with most over 60 and some at 70 and now my Author Score is rising steadily as well.
4. I have added some back links from my web site and through some articles published at EzineArticles and now await the results for these but hopefully as they are bringing external traffic to my hubs this will increase my author score some more.
I think the above is a good reflection of how hub pages work. In other words, add quality articles over time, not too many at once and get some links pointing to your profile from other sites, forums, web sites or ezine sites and watch your profile score rise and get more traffic. Rinse and Repeat!!
I hope this helps any other newbs!
Thanks again for your answers.