Your profile says you're a T1 - I doubt very much you'll be kept just on Bolus.
The DN's can be far more experienced than GPs regarding Diabetes as they get specialised training on it. So the DN will guide you on changes/adjustments and the Basal (I actually don't know why she didn't add that in too, sorry, I'm new myself).
Basal is for background insulin, it basically trickles throughout the day and night as does the insulin our Pancreas make in non Diabetics. Obviously in T1 (and in some cases T2) the insulin production becomes deficient (T1) or defective (T2) so the Basal or background insulin basically is there as a safety net because during the day and night if you don't eat the body will dump glucose held in reserve in the liver so the basal keeps that steady.
As an example. I had a morning reading of 9.7 - I only took my Basal and had no breakfast and 2 hours later I was at 9.3.
Are you on small dosages of the Novo? You say your range is 4 -10 are you getting any hypo feelings when your glucose level comes down? Are you dropping quickly and have a large reduction in glucose after a meal? If not, don't be too worried for now and keep testing your sugar and especially if you feel weird or ill and as soon as anything happens that does cause you worry or you feel ill just call NHS24.
You will have many questions as I do! I'm also unsure about adjustments for the gym etc but I'm not going to be working out for a week yet as I've got a chest cold anyway and it's the time of year to forget about the gym :lol:
I'm sure a more experienced T1 will be along to elaborate much better than me.