Hi curiouscat and welcome to the forum
Grant Thornton are a great company to work with, I know the partners who work there very well, and if I ever needed to do an IVA they would be my first point of call - as I cannot do my own!!!
Turning to the children, just be honest and explain to them that Mummy and Daddy are going to have to cut some of their expenditure, because costs are rising and it will be important that every penny is spent on important things, and that treats have to be saved up for. You will find that children are often more resiliant to change than adults, and can easily adapt - and get them involved in savings by opening a post office account for each of them to put their pocket money in. Tell them it is a competition out of all of you to see who can save the most.
Regards, Melanie Giles, Insolvency Practitioner