Does your Jensen radio indicate it is SiriusXM "ready"? If it does there will be a connection somewhere on it.
I have a 2013 Freelander on the Chevy chassis. I removed the Jensen radio (FYI, replaced it with a Kenwood). The Jensen radio unit came with two L shaped metal tools about 3" long and 1/4" wide used to release the radio from the dash after the face plate was removed. Look in your manuals for the one for the radio. Removal is explained there. Hopefully the tools are with the manual. Easy access if you find the tools.
Search the forum for Sirius or SiriusXM. There are several with pictures and recommendations for installing the antenna without penetrating the roof. I have one or two and have responded to a couple. These existing threads should help you.
My Jensen
My SiriusXM component located behind dash and below radio.
My SiriusXM antenna Velcro'd to vent fan.
Paul