Negotiating interest rate with bank

I'm currently with PTSB.

I am in some negative equity as my house is worth €85k at best but the outstanding loan is €115k. The interest rate is 4.55%.

I rent out my house and it currently covers the mortgage (although repairs, insurance, tax and impending water charges and property tax will remain my burden).

I have been forced to come to Canada to work but would equally consider living and working in the UK. I'm pretty annoyed that PTSB are increasing their variable rate on what they would consider a performing loan, especially given that the ECB rate has not budged.

How much negotiating can one do with the banks?

For example, if I told them I would have no problem ceasing payments, allow them to liquidate the property at a knockdown price leaving me with say €50k unsecured debt, and I could simply get a part-time job and a lease in England and declare myself bankrupt (proving the outflows of the property pushed me over the edge)... would that be enough to change their mind about bumping up the interest rate on my loan?

Note: I'm not looking for a discussion on either ethics, responsibility or bankruptcy tourism. Simply an opinion on whether individuals can negotiate interest rates with banks.

I couldn't imagine how they could negotiate differing rates for individuals given that they form part of a contract involving a large number of people in a similar position. I presume all PTSB variable rate customers have similar contracts. To advantage one person or group of persons (who happened to ask them for a reduction soley because they were unhappy with the interest rate) would effectively equate to unequal treatment.

Mortgage arrears and negotiating with mortgage provider

We are in a situation where we have negative equity with an investement mortgage to the tune of €250,000 against two properties. My wife works, but I have been self employed for the past 7 years and am not allowed to claim any social welfare benefits as a result.
We are now in severe financial difficulty and have tried unsuccessfully to re-negotiate our flexible rate mortgage with Permanent TSB, this is against the backdrop of falling rents and punitive increases by Permanent TSB mortgage rates.
The bank have said that they are unable or unwilling to change the rates. Does anyone have any advice, or does anyone know if there are any legal challenges or judicial reviews pending in relation to the fact that the bank are advertising rates far lower than we are paying, but won't give these rates to us, and also that the bank appear to be abusing a position of dominance.
Is anyone willing to finance a legal challenge which will help force the banks to agree terms were arrears are in place?