The application form shouldn’t be submitted by your solicitor from within the UK. This should be submitted from outside the UK by the applicant. The Home Office can trace the IP address of where the form was submitted and it can result in a refusal if they happened to do that. This isn’t always the case, but it is not worth taking the risk for the sake of a couple of clicks.
The process for documents has become a little more complicated at the moment. The new system should allow you to upload scans of all the documents to the VFS website in order for the Home Office to consider the evidence, this cuts out the need to submit any originals. However, the upload system is faulty and hasn’t been working as intended. We have found that applicants in the US have either been told to post their documents to New York, or alternatively, the visa application centre officers have scanned the documents for the applicant at the appointment and subsequently nothing has to be posted.
Documents are no longer posted to Sheffield, this changed a number of weeks ago.