Thanks for the responses both! The soft focus effect is more pronounced due to the image scaling and reduction to post here, but it's not going to change the effect noticeably. I bought a job lot of around 50 screw on lens filters- was a bargain from a certain auction site as I got some I wanted (colour for B/W etc) and cost well under a £1 per filter, so I wanted to experiment with some of them.
These were the result of a 'spot' Hoya filter, where the centre is clear but the rest has a diffuse effect. I'd stacked a Jessops polariser onto this as well on my Super Takumar 135 f.3.5- I suspect the extra layer of filter from the polariser enhanced the softness and I'll have to try a couple of shots with just the spot lens.
I hope so too Rob, but so far no email.
Brian, no offence ever taken, I genuinely feel the effect is overkill here and not quite what was hoped, but this was the first time I'd tried it with this lens, so may produce other results on different lenses. I concur regarding the colours in the first shot, they required a slight adjustment using the picker in Rawtherapee to get a slightly warmer balance- my Pentax tends to select a cooler temp if left on auto.