So damn close to finishing my first ever build (pretty much the first thing I've ever built since Lego pirate ship circa 1989).

Getting ready to ride when I ran into some chain lengthening problems.

I have an Izumi black chain (the cheaper one), which comes with a funny masterlink and clip, which goes into one of the runners. I popped out too many links and actually managed to reattach one after quite a struggle.
I'm one link too long but I can't remove it because it will be one of the runner ones which the masterlink slots into (either side). I can't move my wheels back either because they have these screwed in tensioners.

Like this:-



What do I do (apart from changing cog/chainring which can't happen for at least another week)?