Failed MOT due to rust - scrap or second opinion?

[JazzyJayyy]

Hi, took my 2005 Jazz in for an MOT, and it had the following two major failures:
    Offside Rear Seat belt anchorage prescribed area strength or continuity significantly reduced outer sill corroded (7.1.1 (a) (i))
    Offside Rear Suspension component mounting prescribed area excessively corroded significantly reducing structural strength axle mounting housing (5.3.6 (a) (i))


Garage quoted 18 hours of welding at >£1k to fix, and recommended scrapping it instead, which seemed fair.
The part of this that I'm confused about, is the fact that it's the offside rear - this hasn't even been flagged as an advisory on past MOTs

I've jacked up the car and taken a look under - it's rusty for sure (it's an 18 year old car!), but I've tried agressively trying to stab a screwdriver through, and couldn't anywhere or see any obvious structural issues near the offside rear suspsension, but I'm also no expert

I've attached some photos of the underside near the offside rear wheel - think it's worth getting a second MOT from somewhere else or just scrapping it?

Ideally we'd like to get another year out of it since it's never had any mechanical issues, and it's not a great time to switch car for us, plus we just put a new set of nice tyres & a new radiator on it this year!

[Jocko]

My 2006 Jazz went to the great scrapyard in the sky last MOT due to rust and I had never had as much as an advisory for signs of corrosion either. Repair costs were similar to those you were quoted. I may have gone down the welding route but a couple of other issues sealed it for me, hence the reason my avatar is now a Skoda Fabia.

[Lord Voltermore]

I am not an mot tester ,and whether its safe is a subjective opinion of the tester. 

Have you read the following from the offical testers manual?
https://www.gov.uk/guidance/mot-inspection-manual-for-private-passenger-and-light-commercial-vehicles/appendix-a-structural-integrity-and-corrosion

Although much of it refers to pushing holes in thin metal , highly stressed components can be failed if there is serious reduction in the thickness of the metal.Not necessarily a hole or flexing.    In your photos there are places where  old underseal may have peeled away a layer of rust, but also  signs of pitted rust where  thicker metal has been 'eaten into'.   But whether this is a serious reduction in thickness I dont know.    You could try another tester but I believe they know from the computer system  that it previously failed  and they may be reluctant to say differently. They might need to justify it to the DVSA    .  I think you can appeal a failure to the DVSA.