Central heating pipework (manifolds?)

[screamer]

I'm going to be moving into my late parents house in the next few months.
was looking to change some radiators but when under the floor i've noticed what looks to be the main flow pipe looping around the house and it has tees coming off to go to the radiators.

Should this not all come from a manifold then piped to each rad?

The end bedroom always seems cold, so maybe not getting enough HW?

 

[screamer]

original story was, when my parents moved into this house, it was steel pipes, when my dad was replacing the rads when doing up the house he changed it to copper.

 

[ianmcd]

Common way to do it, manifolds can be used but dont have to be , probably needs balanced