Well post Germany trip and after the issue on the Autobahn on the way home I am pleased to say all is back to normal.
The lower bolt hole on the calliper has a very damaged thread, and after an inspection and trying to tighten another bolt in to it it's fair to say it's in need of repair. After reaching only a small amount of torque upon tightening the bolt slipped off the remaining threads and went loose again, shows why I ended up in the situation in Germany.
The pics give a small indication of how things look.
I was fortunate to have another front calliper in the garage which needed a bit of tlc, the bleed nipples needed some patience to free up but I got there in the end. Biggest issue with the spare was the poor condition of the dust seals
It was at this point Ryan came to my rescue with a new set of seals and dust covers which he sent to me on a super fast delivery service for a very very very good price, massive thanks my man, total life saver!
So got cleaning and fitting the new kit to make the callipers fit for use.
Then spent today in the rain getting everything switched over and fitted. Happy to say all is working well and back to normal. I will get the damaged calliper off for repair and try to clean it up a bit.
Thanks again for everyone's help on the side of the road, Si & Jo for sticking with me the whole way home at a somewhat dull pace and Ryan for sorting the seals and dust covers in super quick time to get back on the road!