With some of the silages I've seen this year straw would probably have been a better option! The way to make straw feeding work is with top quality ewe cake - 20% protein (including good quality protein like soya at least 10%) and an ME of 13. Obviously that's not much help with the situation at the moment so my next best advice in the meantime would be too make sure you have plenty of good quality artificial colostrum avaialable at lambing in case you do have less milk in the ewes, be prepared to take a twin off any ewes less than condition score 2 and hope for an early spring! I would also make a careful note of lamb losses - although this can be depressing, if you can record how many are lost at lambing and if there is a particular trend (e.g. lack of colostrum, poor lamb weights) then at least you will have the financial evidence next year for being able to invest more in ewe nutrition next year.
I bet he payed more for straw than good hay, local merchant here is on £110 for barley straw you can get hay a lot lessthat was my first tohught before even bought straw but my dad made the choice while i was away