One of the main documents any lender requires to perform their due-diligence is a copy of your business bank statements. Following are links to all the major banks guides on how to download your bank statements.

HSBC

This isn’t an official guide, however the instruction on this page are solid. https://aralbalkan.com/3744/

Barclays

http://www.barclays.co.uk/onlinestatements

Halifax

http://www.halifax.co.uk/aboutonline/things-you-can-do/managing-your-accounts/balances-and-statements/export-statements/?pagetabs=1

Lloyds

http://www.lloydsbank.com/online-banking/benefits-online-banking/viewing-your-statements.asp

Natwest

https://supportcentre.natwest.com/app/answers/detail/a_id/2125/~/how-can-i-get-a-copy-of-my-statement%3F

Santander

http://businesshelpcenter.santander.co.uk/(S(g0apsansnrzx4k453zfknrbl))/_layouts/helpcenter/FaqDetail.aspx?pregId=52

Royal Bank of Scotland
http://personal.rbs.co.uk/personal/ways-to-bank-with-us/online-banking/download-pdf-accountstatements.html

Metro
https://www.metrobankonline.co.uk/Global/Metro%20Bank%20Online%20-%20January%202013/Business/Commercial%20Phase%202/1/2/Commercial%20Online%20Banking%20User%20Guide.pdf

Coop
http://www.co-operativebank.co.uk/business/businessonlinebanking/faqs#CanIdownloadmyaccountactivity?