Hi DJB
It clearly states that the applicant should provide bank statements for the last 6months
https://www.gov.uk/general-visit-vis...u-must-provide
a current passport or other valid travel identification
2 passport size colour photographs
evidence that you can support yourself during your trip, eg bank statements or payslips for the last 6 months
details of where you intend to stay and your travel plans - you shouldn’t pay for accommodation or travel until you get your visa.
..Even the guidelines for supporting documents requires (bank statements /bank book ; bank letter or balance certificate)
https://www.gov.uk/government/upload..._Documents.pdf
please note:
The applicant needs to convince the ECO that she got finances and income and be able to support herself on her visit here in UK and she has compelling reason to return in PH ie long term job;propoerty or / and business.