They take their personalised coat-hooks with them!
No seriously, web site says "preparing for the rugby league test match". But how long does it take to chuck out some chewing gum, tie-ups and liniment?
Go on a ferry ride from Pier Head. Good views of the Liverpool waterfront. If early, can go across to Wallasey and back. 10am and after there is circular ride including Birkenhead. Can get off and get back on later one. Every hour. There is The 'U-boat story' exhibition at Birkenhead.