s.hoskin@xtra.co.nz said:

Thanks for piecing together the logic which can at times be difficult to decipher.

Kind wishes,

 Su. 

  _____    _      __     __  _                  _   _  __
| __ \ | | \ \ / / | | | | | |/ /
| |__) | | |__ \ \_/ / | |__ __ __ | | | ' /
| _ / | '_ \ \ / | '_ \ \ \ /\ / / | | | <
| | \ \ | |_) | | | | |_) | \ V V / | | | . \
|_| \_\ |_.__/ |_| |_.__/ \_/\_/ |_| |_|\_\