Hi godfrey and welcome to the forum
I am a practising IP, and will therefore try and answer this as if you were a client of mine coming for help.
Firstly, as the other posters have said you need to revisit your income and expenditure account to see what areas are causing you difficulties. Are there any reasons for you now struggling, or was the budget always tight. Have you made adequate provision for contingencies, or has any unforseen expenditure cropped up during the last year. Once you have arrived at a figure you feel is a comfortable alternative to the high figures you are already paying, then approach your IP to see if they feel a variation to the terms is possible and feasible.
Don't get too phased by the property issue - a variation proposal can vary those terms in any case, but you will need to get a current property valuation and mortgage redemption statement, as the equity will need to be addressed in some format.
Regards, Melanie Giles, Insolvency Practitioner for over 20 years.
For further details contact me at
http://www.melaniegiles.com and view my IVA blog at:
http://melaniegiles.blogs.iva.co.uk