Hi Lynne
There's nothing to worry about with your insurance. Your proof of insurance will be on your invoice and, as you say, the insurance policy number will be the same as your holiday booking reference number. Your tour manager will have full details of your insurance while you are away.
If you want to check on the cover you have, you can find the information in the back of your brochure or on this website. Click on the 'essential information' tab on your tour to find it.
Kind regards
Olly, your editor