Recaro seat swap difficulties

Hey guys I saw a few guides on here on installing mk4 recaro seats in a Skoda fabia and thought I would have a stab myself seeing as I picked up the driver and passenger recaro seats for £60. 

Unfortunately it appears that the seats I acquired have different mounting points to the fabia seat base.  There is only one threaded bolt per side where I think there should be two? 

Now, is it safe enough to simply weld this onto the base of the Skoda fabia seats, or should I sell these on and try again with another set of recaros? 

Thanks