mediation is worth a try and can save so much time and money, it does involve total cooperation and honesty, in my case it did not work as my ex wife used it as a blaming excise as we had not seen each other for over a year. both have to just be prepared to to be frank and honest, it can be hard on a emotional level if this has not been dealt with prior to the meeting as much as possible. The mediators are experienced and soon realise what is going on and to there best not to let things go off tangent.
Every aspect of ones finances is relevant, taking into account expences debts, earnings, pensions and most important housing needs. You will need to provide full and frank financial disclosure and will be asked to fill in a form E. It is worth while preparing as much information regading your finances as possible, at the first meeting we were asked to provide a summary of our assets and debts earnings etc. Whether it is during or or prior to the seperation all needs to be disclosed whose debt it is can be worked out but certainly needs to be disclosed.
My ex ended up going down expensive court route luckily we ended up settling before the second hearing so could have been worse, she ended up taking what I had offered from day one so we could have saved money and time but we just had to go through the process just to get there.
Best of luck hope all goes swiftly so you can both be happy living again.