I would say they are liable, but only if informed about it and given the chance to repair it. So inform them, and ask them to get it fixed.
Done. They will, I have absolutely no doubt, refuse to do so. Or rather say "we'll get round to it", and then never do so.
If they were informed that your alloy repairs would be charged to them until such time as there is no hole it might get fixed.
Or you could arrange to fix it and get reimbursed. I did that once when I lived in Bethnal Green.
Noticed this the other day. Please let me know their response, happy to apply some pressure too as required.
@Dammit started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
I would say they are liable, but only if informed about it and given the chance to repair it. So inform them, and ask them to get it fixed.