Dear Katherine,
I hope that I have understood your questions corrrectly.
1. The three words in blue are all past participle clauses/-ed clauses.
They have a passive meaning and are in fact reduced relative clauses.
the longer versions are:
.....which is shown; .....which are left; .....which was issued.
2. a) Thank you for bringing(not 'bring') this matter to our attention.
There is only 1 verb, 'thank'. 'Bringing' is a gerund. Use a gerund or noun after prepositions, in this case "for'.
b + c) We apologise for any inconvenience this error has caused.
Please accept our apologies for any inconvenience you were caused last week.
There are 2 clauses in each sentence. The 'that' has been omitted, Ok in more informal writing, and this may be why your question has arisen. The 'that' would be inserted before 'this error' and 'you were caused'
respectively.
I hope that this answers your questions.
Admin.
Regards
Workplace English Training E-Magazine Team