Blue smoke problem when pressing accelerator

Hello,

It sounds like you may have the oil drain back holes plugged in the cylinder head. I would remove the valve cover to inspect. Here are two guides to help us get started:

https://www.2carpros.com/articles/blue-smoke-from-engines-exhaust

and

https://www.2carpros.com/articles/replace-valve-cover-gasket

Please run down these guides and report back.

Cheers, Ken

My car is Mk1 velociti 1.4i. Do you mean the answer could be the same?

Yep, if the oil changes have not been done on time it can cause sludge clogging up the holes.