Jobs that earn £18,600 or more:

[Terpe]

Will a salary of £28000 Be sufficient ?

That's what I earn as a nurse. I do extra shifts so its a bit more.

Just on income threshold UKBA require a minimum gross of £18600 for a couple with no children.
Anything equal to or above that amount will mean that a settlement visa application is compliant for the finance test.
All other requirements will need to be compliant before a settlement visa can be granted.