How to use regular expression to reverse search, and limit more than two conditions

Generally speaking - this is how it should be found in all the examples shown.

first:

Good(?=\h\w{2,3}\d{4})

second:

Good\h\w{2,3}\h?\K\d{4}

Good my1980

(?<=Good my) 1980

By @dublove

You don't need the space after the bracket. 

(?<=Good my)1980

"my 1980" or "my1980"? 

Actually now that I've thought about it, the problem is very likely that RegExp in JavaScript (including ExtendScript) does not support positive lookbehinds. You can use findGrep() instead, which does support it. Search for a script example that used findGrep. 
-Mark

Hi @dublove, are you doing a grep search via the UI or via ExtendScript? If via script please post the section of code and we will get to the bottom of it.