No, it means you DON'T have to.
The form is saying "we require you to provide this information but we recognise that, under the provisions of the Rehabilitation of Offenders Act 1974, you're not required to disclosed 'spent' convictions".
Irrespective of what it might say on any form, you're never required to disclose spent convictions other than in relation to those types of employment which are exempted from the provisions of the Act. (They're principally jobs working with, or alongside, children or vulnerable adults. Employment related to the 'administration of justice' is also exempted).
In relation to the type of questions you're referred to, the Act states that you may lawfully 'answer accordingly' (i.e. lie). 'Ancillary matters' are also covered by the Act. If, for example, you were refused insurance solely because of an unspent criminal conviction you could later (when that conviction became spent) lawfully answer 'No' if you were asked "Have you ever been refused insurance?"
Chris