Set LR - asked to send all passports issue

Please help!
ILR (10 years route) applied 04.09, received e-mail yesterday from case worker asking for all my passports to prove absences. I only have the current one and lost 2 old passports. My solicitor is requesting a SAR record and I will send a letter from my employer confirming my holidays absence only for the last 7 years. Is there anything you'd recommend I should do? I will write a letter explaining I lost them, and will try to attach all flight tickets for the last 10 years.

Do you not even have copies of old lost passports? If not, then the steps you already are taking is the best bet.

Ideally you should have reported them lost and got a police reference number also.

What kind of a solicitor is this who did not even know that you have to prove your residence for the last 10 years?!