Some people fit a normal dash clock onto the blanking plate where the clock goes , something like an old smiths one with a chrome bezel, just need to make a 60mm hole. If you can find one out of an old vauxhall they have the silver bit in the middle that matches the other pods on an early bay. They normally go for about £20, bit cheaper than an original deluxe if you can get one.
If your worried about wether a mph speedo will work on your bus I have a good late bay one you can try for nowt.