Can I have half a wall sand & cement & half dot & dab

[Blackiwoods]

When they replaced the skirting they replastered from back to brick but only about 1/4 of the wall up. The rest is old plaster that I have knocked back to brick. I can dab and dot so to save money and have a good finish which of the following do I do.

Back to brick all of it?
Dot and dab where the old plaster was and leave the newish plaster where it is?
Sand and cement where the old plaster was?

Or do I have other options?

Thank you for any help, I really need it!

 

[dontbelieveawordofit]

either. or bonding coat where the old stuff is,

 

[Blackiwoods]

Thanks benny. Which would you do?

 

[dontbelieveawordofit]

if the walls are bone dry and no chance of damp bonding coat