What you've missed, Genghis, is that only certain NOTAM series are available on the Norwegian site. The EGTT brief gives mostly series B and some series E NOTAMs.
What's missing is, for example, all the Nav warnings, which come in series H. For example, there's a BBMF flypast at Henlow today, and a PJE at Colchester. They don't get a mention on the Norwegian site because they are series H.
Not all NOTAMs are disseminated outside the UK, which is why it's important to use a UK source for flights originating in the UK.