You will need to appoint a 'Power of Attourney' to apply for the bankruptcy for you - may i suggest you contact Paul Johns at Reviva (see experts button on left hand side) he has vast experience in this area, and has helped many clients through this process
Melanie Nicholas 28 years insolvency experience - 23 of which in the Insolvency Service - Insolvency Manager Jones Giles email me at melanienicholas@jonesgiles.co.uk
As Melanie mentions Paul Johns from Reviva UK can assist you here with the power of attorney but it isn't difficult to declare BR in person.
If you are living abroad you would need to fly back to the UK to petition at the High Court in London. The process is all done on the same day and costs £522.
Speak to Paul and he will provide more information about the power of attorney and the associated costs and then you can weigh up the options.
You can only file for BR when you are residing outside the UK if you have lived in the UK within the last 3 years and you do not live within the EU (except Denmark).