Only you can really make that call.
What I can tell you is that the TDI hasn't even done delivery mileage on 118K

These will merrily go to 500K with basic servicing and generally the engines are solid. The autobox isn't the most sophisticated in the world but again, can cover good mileage if looked after. Change the autobox oil!! As long as its maintained you'll have no issues and with parts for these getting cheaper and cheaper you should be able to repair those issues for next to nothing
1) SRS is likely the clockspring unit, easy enough to change but the light is latching for all faults so will need to cleared once the issues resolved
2) Would guess at sump, the plug is steal into aluminium so easy to strip the threads. New sumps are £25 delivered on ebay.
3) Unusual tbh. These aren't known to be rot boxes, the only exception being the out rigger box section (which is near to the area described but nearly always called as such. Welding is fairly cheap these days, a lot of mobile welders advertise on facebook at the like so it's unlikely to be very expensive.
Everything else you've mentioned are common faults, all of which are covered in the KB's on this site, and all cheap and easy.
Welcome to the group
