In reply to William Connolley:
I travelled London-Brussels return twice this year, in March and August
The outbound from London was smooth both times, I just told the security before my equipment went through the xray that I had an ice axe.
for the return in March 2023 from Brussels, i showed the douane/security a copy of email received my the president of the eagleskiclub and after much argument the actual trainconductor for my train past by and he said to drop off my bag with the ice axe at the locked compartment on the train next to the first class carriage. And to find him again after the train pulled into St Pancras.
for the early August 2023 return from Brussels, i told the douane I had an ice axe, showed the eagleskiclub email but was immediately told that it was not allowed. I argued that everything was fine for my previous trip in March, but was told rules are different between those of the brussels security and eurostar; And that the eagleskiclub email was for eurostar and not the brussels security. Luckily the belgian friend who dropped me off was able to retrieve it and keep it for now. I have just emailed eurostar requesting confirmation of mountaineering equipment specially for the Brussels station but doubt i will get a reply.