In order to claim Unfair Dismissal an employee normally has to have qualifying period of employment. This qualifying period of employment is a period of not less than one year ending with the effective date of termination.
There are some exceptions to this requirement for a qualifying period like dismissal on the grounds of pregnancy for example.
Questionnaires are used in the Employment Tribunal process in cases of equal pay or discrimination. In such discrimination cases, information can be requested from an employer or other respondent by use of a questionnaire before any claim is presented to a Tribunal. The forms are prescribed in schedules to the relevant legislation.
The questionnaire enables a prospective claimant to find out information which may assist the claim for example the relative numbers of employees from a specific racial background that are employed by the respondent. There are time limits for presentation of the questionnaires and the respondent is not obliged to reply. However, a failure to reply within a reasonable time as set out in the regulations the Tribunal can draw an adverse inference from the failure.
It is important to note that a Questionnaire is not a grievance. You can read the EAT decision on this point here.