Answer:
Unfortunately, due to many responsibilities, we will not be able to make it to the meeting in London in this period. We would be delighted, however, if you considered paying a visit to us.
Step-by-step explanation:
It's important to know the difference between informal and formal English. Informal English is used in everyday conversations (e.g. with your family and friends) and personal letters. Formal English, however, is used at your workplace or school, with people you aren't close with, and in other situations where you need to appear professional and polite. For example, instead of sorry, when speaking to someone formally, you could say I apologize.