Apollo,
Our purchasing department say ARJO have the national contract for hoists etc. so are easy to deal with - no tendering etc - and give a decent price because of this. So we have all ours on contract as some of the work needs a certificate to do it.
Beware of LOLER (Lifting Operations and Lifting Equipment Regulations 1998). Everything thats primary function is to lift comes under these regs. If it lifts a person it needs twice yearly checking by a properly accredited body. i.e. not in house hence the contract.
Robert