We need a photo to give any real advice but if it is close to a wall that may well be part of the problem.

3 ft away from an outhouse wall (part of the kitchen) & its spread faster this year. It was "small" for years but after 23
the profusion of flowers is staggering but I guess less needs to be the order of the day

I have one against the wall of our shed, silly place but it's all the space we had at the time. I prune it every other year and it still springs back and flowers like mad.

I used to work at s hotel where they had a conservatory with a patio outside and the most enormous camelia planted into it. It was so large and beautiful that it had a preservation order on it but the gardeners were able to chop it back when it got too out of hand. It thrived in its limited space.

When you say 'it seems to have grown too tall', perhaps the variety you bought is one that gets very tall and possibly wide,you haven't said which variety it is. Camellia japonica varieties, though variable in ultimate height and spread, can be expected to make 6--8 feet, but others, such as C. Adolphe Audusson or C. 'Donation' get up to 20 feet. Therefore, depending on the variety, this might be a case of 'wrong plant, wrong place', so although you keep cutting it, it just keeps getting bigger because its programmed to do so.

Yes it is a Donation.......I was so small for the first 5 yrs. I wanted it close to the wall at first & it quickly bulked up. The trunk is big now. I cut it every yr & I guess keeping it away from windows & gutters is a priority. My nbr has a tri colour on a west facing fence & the best branch broke after a storm......then the next best broke & after 3 yrs its a mess as nothing is growing east to balance it up

Ah, then it wants to get up to 20 feet... and will keep trying!