I want a dwarf wall building with glass surroundings but a normal
roof, ie tiled. Will this classify my buidling as a conservatory?

No. Indeed you may find it illegal to build your intended building.

You need the conservatory exemption to be able to have glass walls. As it
would count as an extension, the glazing would be above the maximum allowed
for simple uValue calculation and it would be very difficult to achieve the
right results using the other methods.

The only method I can think of that may be successful is showing an
improvement over the entire property. i.e. the calculated heat losses in the
new extension must be matched by improving insulation massively in the rest
of the property, so as a whole, the building is more energy efficient than
it was before the extension.

Christian.