Hi Pim, I’m the chairperson of my local gardening club and over the last 2 & 1/2 years I’ve just renegotiated the lease on our members only store aka trading hut, it’s our building but on land we rent via a 28 year lease from the Parish council. In the updated & original lease it states that the signatories from the club are trustees of the club, and this will be passed on to others within the club. So I believe it just means I hold the office of chairperson & the other committee members the same & act for the good of the club & take reasonable care to keep the club financially viable etc & stick to the constitution of the club.
I know of your difficulties with your allotment,so maybe find out what the constitution is might be worthwhile as the committee cannot do things out of that remit.