You will need someone robust. But you are not talking about high value assets and as such I would suggest you avoid the high ranking London firms as you may end up spending hundreds of thousands in fees.
When assets are worth millions, this is justifiable. When they are not, its a folly.
The good news is that you can make the application yourself, you don't need a lawyer for that. If your wife has been abroad for 5 years you could file for divorce on grounds of five years' separation, which doesn't require her consent.
You can also issue a financial order application as your wife lives outside the UK and as such you would be exempt from mediation.
You can then engage a lawyer for a court hearing if you need to, and save money on expensive lawyer fees. I'd suggest going to a barrister directly for court representation through direct access, perhaps see my www.barrister.co.uk for that.
The forms/ links you need are here:
This is also a helpful guide for the financial order process: http://alc.org.uk/uploads/Applying_for_a_financial_order_without_the_help_of_a_lawyer.pdf
Can I clarify anything further for you at this stage?