If you have ILR, you're regarded as a permanent UK resident, and I don't think it really matters to UK immigration authorities who you are working for - or indeed whether you are working at all. You only lose ILR if you leave UK for more than two years, and I really don't think you will have any problems in coming back early next year.
I think you might like to consider taking professional advice as to your obligations to this employer - in particular whether you are contractually bound to return to your home country to serve out your notice, if that isn't what you want to do. (I note your use of the word "forces"...)
paul