I need to clean up some text.

- I need to remove all instances where < occurs as first and only char on a line (but keep the line empty):

eg

the cat sat on the mat
>
the dog sat on the cat


- I also need to remove instances where we have uncessary < followed by a space and then a <b> (first char on line)

eg

< <b>The cat sat on the mat

and finally I need to make sure that each line that only contains <b>...any text in here...</b> has one empty line above it (except for the first occurence in the whole string being processed)

Anyone able to help put this into a regex?