Proof of work experience question (payslips, contracts etc.)

[PaulOK]

Hi,

 I have a similar question to Nathan below. On my Skilled Worker application it wants details of my employment going back to 1998. Sure, I can provide all this and as a contract design engineer I have had about 5 jobs in that time. Later the visa office will require proof and I only have proof of employment for my last three jobs dating back to 2004 (in the form of pay slips, contracts, letters of engagement etc.). 

Will I need proof for the two jobs I worked between 1998 and 2004? I could contact my original employing agencies (who are hopefully still in business!) and see if they have my original contracts in archive. They may or may not and I wonder if it's necessary.

Thanks in advance for any help

Paul in Surrey