Cant remember the location, but a few weeks ago a very long thread about the poor fitment of a child seat led me to query the retro-fitment of an ISOfix. Omegas did have them as an option. Presumably there are lovely holes waiting in the bodyshell for you....presumably!
As far as I can tell, on principle, it would be do-able to retro-fit it. No doubt there would be various scary issues like 'ahh, what if you dont do it right!?' 'No no no, cant be done' 'Factory-fit only' 'you'll kill everyone!' etc...But if you ordered ISOfix on your brand-new Insignia, say, and it arrived and they forgot to fit it I don't for a second imagine Vauxhall would ship the whole car back to the factory, tear out the whole rear trim, fit it, then ship it back to you. No. What would happen is the dealer would retro-fit it according to the exacting specifications they have in their very detailed 'haynes-esque' manuals. It happens when a car arrives scratched/dinged, they respray it, but just don't tell you.
Doing that on a week-old car, or an 8year old one should make no difference. The issues are
if the ISOfix mounting holes are there,
if you can get the 'kit' including correct bolts and
if you trust yourself to do it!
If someone ripped a seatbelt, I imagine you'd have no worries getting a replacement, and fitting it to the car yourself. So I'm not sure how this differs.
Like I say, just be mindful of them three 'ifs' above, please don't go drilling your own holes into steel that may not be the correct thickness/strength to take it!
If it's do-able, it's do-able, if it isn't, it isnt!!
