Thank you, Pamela, I looked it up and you're right, it must be B.spectabilis. A bit different leaf form, not smooth leaves as B.glabra, but slightly hairy. The main difference is the blooming cycle, B.glabra blooms repeatedly, B.spectabilis seasonally responding to hot, dry weather. Glabra tolerates cooler conditions better. Spectabilis looks worse in winter than glabra.
The branches with the vicious thorns were reaching one's head dangerously, so I took some branches completely out as I wasn't sure how to prune it in order to maintain the chalice character. If I would have just shorten the branches it would probably make too many side shoots. I will leave it as it is until February. There was a controversial information about the fertilizer, some sources recommending a nitrogen feed, some a phosphor feed. Generally the recommended pH for bougainvilleas was 5-6,5.