I have a small lamppost fixed to the ground with threaded bar (set deep into 2' of concrete). Unfortunately the M8-sized bars aren't long enough to go entirely through the base of the lamppost. My plan is to use an M8 to M6 reducer as I have a long length of M6 threaded bar which can extend the bar up. Unfortunately there's only 15-20mm of room underneath the base of the post so I don't have a lot of room to extend the thread. I need a reducer from M8 to M6 with an overall length of no more than 20mm. I can't find them in the UK or even at the local fastenings shop -- the only source is from a seller based in Honk Kong and the delivery time is up to 4 weeks. Something like this: Does anybody know if this is something available in the UK? Maybe I am looking at the wrong solution?