Sorry – forgot a few things! The dealer is under no obligation whatsoever to refund your optional extras. No harm in asking, but I’d manage your expectations!
Secondly, as you are likely to be in a hire car for many months, I wouldn’t just accept whatever they are likely to give you. The first few times I had to have a hire car I had a Vauxhall Mokka and an MG ZS. Both were truly dreadful cars. The last time I needed a hire car I asked Motability for something better and got a Mercedes GLB. As it happened, the Merc had a major fault (digital dash kept failing), but you get my point!
Finally, I’d make sure that you physically check that all the mobility kit fits comfortably in whatever car you order, rather than just go on measurements. One or two people have commented that the tailgate on the latest Kuga is sloped (unlike your Tiguan, which has a squarer back end) and this causes some people a problem with loading large mobility aids.