Hi all,

My first time posting on the forum, please let me know if I'm in the wrong area or need to change anything

I brought my 2003 WRX in for an MOT this week for the first time since buying the car (+ the MOT extension). It failed pretty badly due to rust. I've posted the full list below, but the TLDR: rusty sills both sides, and rust at the rear suspension strut mount.

• Front Sub-frame corroded to the extent that the rigidity of the assembly is significantly reduced (6.1.1 (c) (i))
• Offside Front Integral body structure or chassis has excessive corrosion, seriously affecting its strength within 30cm of a body mounting seat mount. (6.2.2 (d) (i))
• Offside Rear Integral body structure or chassis has excessive corrosion, seriously affecting its strength within 30cm of a body mounting suspension mount. (6.2.2 (d) (i))
• Nearside Rear Integral body structure or chassis has excessive corrosion, seriously affecting its strength within 30cm of a body mounting suspension mount. (6.2.2 (d) (i))
• Offside Rear Integral body structure or chassis has excessive corrosion, seriously affecting its strength within 30cm of a body mounting top strut mount. (6.2.2 (d) (i))

I'm looking to get this fixed, and I'm primarily asking for advice or recommendations.
The two things that dissuade me from just going to a body shop and getting it done:

• I want the repair to be structurally sound and to not rust again in a few years (of course), however past that I don't mind how it's repaired. If it's easier to just cut the whole sill out and weld in a steel box section from underneath, that's good with me.
• I've always done all the work on my cars myself, and I'm always wanting to learn. I can't weld (yet), but I would love to be able to help out / see how a job like this is done. I'm keen to help with any other mechanical things like disassembly if required.

I'm in the Oxford area (and also the Bath / Bristol area) - if anyone has recommendations or suggestions for places to contact I would love to hear them I have some pictures as well if that helps.

Many thanks!