Have you tried looking at venues in low season on quiet days?
I am getting married on a Sunday in February and the price difference to getting married on a Saturday in summer is ridiculous! Having our wedding in winter was really the only way we could afford our venue. Venues are usually cheapest during the week.
Are you set on a dry hire venue? Because truthfully, it will probably be cheaper to use a wedding venue on a weekend in low season than try to sort out a whole wedding yourself - I looked into it and the numbers just don't add up. For me to get married at the registry office, followed by hiring a village hall with a hog roast caterer, was coming out similarly priced to the wedding venue I booked - and my venue is a lot less effort and requires no set up/tidy up afterwards.
What are your numbers?
i'm not sure where in the midlands you are, but this pub/barn wedding venue does a package including ceremony, venue hire, and all food and drink, and for 50 people the cost would be £3225. That's incredibly reasonable IMO.
I have no idea how many people that pub holds, they may well be able to cater for 100+...all you can do is look on your local authority website to find a list of all licensed wedding venues in your area and comb through them - that's what we did.