Whilst it was pre-cooking, I did notice it had quite a strong, slightly sour smell, but as it's been ages since I used any GF flours I couldn't remember if that was normal.
The topped and baked pizza did look nice, it even cut quite well although was a bit crumbly (as I expected)....definitely a knife and fork job, it wouldn't hold together enough to pick it up with your hands, the pastry was too fragile and crumbly for that.
But the taste.....it wasn't good at all, a strange sour and bitter taste. On reflection, I reckon it was the soya flour, I think it had gone off/rancid (I'd thrown the packet away so don't know what the use by date was....the rice and spelt flours were in date and smelt fine in the packets). We scraped the (lovely) topping off and chucked the base into the recycling bin. Oh well, that'll teach me not to smell things first before using them!
I shan't be defeated though, I'll buy some more gram flour when we next go shopping and have another go.