it turned out that the time taken to clear/set cs pin and the impost of two extra pins was as waste of resources an an unnecessary
complication. it works fine with out it
Yes, it works fine without it until it doesn't.

The SPI slave counts 8 clocks on SCLK in order to set BF to let you know you have a byte.
When the slave uses the SS input, that bit counter is reset when SS goes high. That keeps
you in sync with the master.

Without it, if there's ever a single glitch on the SCLK line the bit counter will be wrong and you can never resync master -> slave.
That also means that when you first power up, depending on who gets initialized first, there's a chance that the slave could see a transition on SCLK and you never get sync'd to begin with.

@Sheldon - I reread your requirements and I have to admit I'm not sure what you're trying to do.
If I read the comments correct you say that the slave isn't going to use data in. What would be the purpose of the slave?