Hi,
Looks like the 1.5 Ecoboost uses a water-air intercooler:
https://www.ebay.com.au/itm/FORD-OEM...EAAOSwCDZa2cvG
It's probably hooked up to this electric water pump:
https://www.ebay.com.au/itm/Water-Pu...kAAOSwdMheX5PA
and as you can see here, the 1.5 ecoboost intercooler radiator only has small water hoses: (no air going through it)
https://www.ebay.com.au/itm/FORD-KUG...frcectupt=true
I can't find photo of the reservoir anywhere. Could you try to follow the hoses?
Also, try reading the booklet in the glove box. If it is a separate circuit it should have a reservoir with a filling cap. (Similar to what old Subaru Legacy had).
Cheers,