Anyway time for some Q&A again:
for the surface rust i believe can be cleaned using brasso or sandpaper.
Yeah but get some professional or knowledgable advice before you do anything
but how can you tell if its only the surface?what are the signs of corrosion?holes?
because it looks just like that...on the surface...no big bubbles or holes where you can see the road going by
do you normally replace the whole panel(or cut it and wield it back?) or are there ways to get rid of rusts?
Not always...depends on how bad the rust is....most people just treat a rust problem by going back to bare metal.....but...yep you can cut and weld new panels on for bad rust repairs
how much are you looking at for a whole respray for the size of a mini?
$400-10,000??? how long is a piece of string...depends on what sort off job you want done and the materials used
the older models engine run on carb?and how does it work for a 1100cc?
The same....they just have the one carburetter, unless you have a Cooper or someone has fitted twins
How can you tell whether the interior is well maintained or well done?what checks can you do for the interior?
Just by the general appearance, scuff marks, worn pedal rubbers, cracks or tears in the vinyl, worn out seat springing,shabby or no carpet, etc etc
(apparently the ones i can think of is the quality of the seats,the dashboard,the steering wheel and its horn,windshield,roofing,carpet,panel under the carpet,panel under the rear seats,seat belts,door interior,handles,windows)...
yep
so i can guess that its normal if the engine has not been rebuilt,
after all these years ....NO! they probably have had a rebuild
there sure will be rust around the engine component and the mainbody that holds it?even the area where the wiring is?
Rust in engine compartment (especially around brake and clutch master cylinders() is common, front subframes are usually protected by a coating of oil
Old wiring can be corroded, have brittle insulation or dodgy connections
is it possible that the roof will be rusted yet hidden with headlining?
Possible ....but unlikely.....good luck