Thankyou everyone. Sometimes you just need to wail at someone and as I don't have any sewing buddies you guys are my "go to" in times of despair despair!
I hadn't thought about moving my needle over a bit so will try that. Yes, I think you're right everyone..there is something in my seam allowance and pressing that's causing the hassle. So, with a new day and armed with all your advices (plural of advice? Does advice need a plural...hmmmmmmm
)I shall sally forth again to the sewing room....and yes....I'll breeeeeaaaathe and chant restful noises
It's an hour and a half later and I've binned the lot. The 710 won't let me move the needle over while using my 1/4" patchwork foot; I have to use a wider foot and swap my needle plate to a 5mm needle hole and now I can't get the presser foot pressure right...the fabric is slipping all over the place with the wide feed dogs and yet I am getting puckering in my seams and the patches are coming out even more wonky. Yes, my strips are accurate and no, I can't figure it out. I've switched back to the patchwork foot and tried using a guide to snick the seam in to just a scant 1'4" and leaving the needle centred but the wretched things whilst coming out a bit bigger are so cockeyed it's ridiculous. I just give up.
I've lost interest in it and I'm done with it.