Do you mean advise your employer or are you an employer and you are wondering about whether you need to inform your employee. If the latter, then employees are always contingent creditors, and thus would need to be notified.
Why would this company use a courier to collect your documents? Why not just send you a list of documents you are required to produce, and have you post them to them or scan them electronically? Did you keep copies of the documents?
It is great to see that you have your new bank accounts already set up, and if you have disposable income right now to pay something to creditors then you should only do so on a pro-rata basis. In reality it makes little difference whether you pay them or not, whilst an IVA is being prepared.
How did you come across the IP firm you have chosen to represent you as a matter of interest?
Employer notification depends on your type of employment and your terms and conditions. But in the norm you don't need to.
If you are unhappy with your chosen firm you still have time to reconsider. Use www.iva.com to read about other recommended firms and contact two or three of them for opinions on what is best for your circumstances.
With regards your bank account ...i would look to move your direct debits etc and start using your new account as soon as you can.... With regards to payments to creditors before your IVA is approved ....this is a good opportunity to build a small contingency up for when in your iva. Once your creditors ave been informed that you are applying for an iva then i would stop paying and build that contingency.
Sharing from experiences of dealing with debt
There is a solution for everyone .... Just need to stay positive !