Too cheap by far, the work you have described is simply cosmetic.
The rust on the Bulkhead (no it’s not a pillar that’s the bulkhead) needs nipped in the bud rapido like. The repair needs to be made (panels available) ALL the crap need to be got out of the voids and spray all the internals very generously with waxoyl making sure the drain holes are clear.
Once the door skins really start to go there is not a lot you can do to bring them back, basically you are looking at electro-catalytic corrosion (ally skin over steel door frame) the curse of landys.
The key to salvaging the the door is to get at the bit of the steel frame that is causing the rot in the ally door skin. That’s why it’s important to clean the bottom of the doors and make sure the drain holes are clear.
But £265 is just going to make it look good for about 3-6 months, you need to tackle the root causes.
Waxoyl and washing are your friend no matter what the macho idiots say about filthy landys looking the best.
Find somewhere where you can “gently”* steam clean the underside at least once a month in winter
*gently as in not to strip the sealant off