I have an issue with the kitchen sink. The water won't drain away. I
have had a look at the plumbing under the sink and it is a U bend as
follows.

\
\ \\\\\\\\\\\\----
\ \
\ \
\\\\\

There is a step as shown above after the u-bend but no trap. there is
an elbow attached to the u-bend which means the water has to rise
further before falling. Is this causing problems or is this OK.

What actually happens with a full sink is that water only drains away
very slowly indeed.

The washing machine is also connected under the sink to share this same
drain.

Anyone have any comments as to my next steps to try and solve this
problem or anythink i should be doing?

Many thanks for any assistance.