thanks - that's interesting - and any 'per week' figure is only a fluid ball-park to create a headline.
I've found the 'Cash' donations line in both Charities financials.
Interestingly the IBSA is showing a huge increase in the latest accounts (31 August 2016) of £39 million, up from your £14.5 million figure - I've linked the PDFs I used below
(41 + 39) million / 138,261 / 52 = £11.12 per week
Darkspilver, the websites you link to are summaries of WTBTS and IBSA financials. I downloaded pdfs of the actual financials last year. (I tried to attach the pdf's; I don't seem able to.)
Have you checked the 'Documents' tab on the Charity Commission's website? Are they the documents you mean? Or, are there others?
International Bible Students Association
http://beta.charitycommission.gov.uk/charity-details/?regid=216647&subid=0
Click on 'Documents' tab:
31 Aug 2016 - http://apps.charitycommission.gov.uk/Accounts/Ends47/0000216647_AC_20160831_E_C.PDF
31 Aug 2015 - http://apps.charitycommission.gov.uk/Accounts/Ends47/0000216647_AC_20150831_E_C.PDF
31 Aug 2014 - http://apps.charitycommission.gov.uk/Accounts/Ends47/0000216647_AC_20140831_E_C.PDF
31 Aug 2013 - http://apps.charitycommission.gov.uk/Accounts/Ends47/0000216647_AC_20130831_E_C.PDF
31 Aug 2012 - http://apps.charitycommission.gov.uk/Accounts/Ends47/0000216647_AC_20120831_E_C.PDF
Watch Tower Bible And Tract Society Of Britain
http://beta.charitycommission.gov.uk/charity-details/?regid=1077961&subid=0
Click on 'Documents' tab:
31 Aug 2015 - http://apps.charitycommission.gov.uk/Accounts/Ends61/0001077961_AC_20150831_E_C.PDF
31 Aug 2014 - http://apps.charitycommission.gov.uk/Accounts/Ends61/0001077961_AC_20140831_E_C.PDF
31 Aug 2013 - http://apps.charitycommission.gov.uk/Accounts/Ends61/0001077961_AC_20130831_E_C.PDF
31 Aug 2012 - http://apps.charitycommission.gov.uk/Accounts/Ends61/0001077961_AC_20120831_E_C.PDF