He he.... old funny thing.
The first 4-cyl Kompressor engines on early W203 (that's the code for the C-Class model from 1999 to 2007) where indeed 2L.
Around 2002-2003 the basic 4-cyl Kompressor engine was replaced with a new unit, code M271, which is 1.8L.
It came in three flavours - 180K with 141-143BHP, 200K with 160-165BHP, and 230K with 190-195BHP.
All three engines have the same basic engine block, with the 1.8L capacity. The higher power output was achieved mainly through lower compression ratios and larger Kompressor units.
So you are lucky to have the M271 / 1.8L engine with the higher output of the two engines commonly fund in the UK (180K and 200K, the 230K is very rare). Enjoy!