My partner handed her complete visa application to bkk 3 weeks ago.   

1.  How long do these usually take on decision. 

2.  From start of visa

(If granted) how long of a space do I have to book her flight. Do they give you a 3mths or 6mths time span in which to book flights and make time/ date arrangements. 

Thanks in advance

Should be about 3 weeks from when she went to VFS, so any day now.  The visa is valid for use from date of issue to expiry - 6 months presumably in your case?  You can enter any time in that period but must also leave before the expiry date.

1 hour ago, Upnotover said:

Should be about 3 weeks from when she went to VFS, so any day now.  The visa is valid for use from date of issue to expiry - 6 months presumably in your case?  You can enter any time in that period but must also leave before the expiry date.

Thanks 🥇