Nigel
If you haven't used these batteries for that long then they will probably be dead, or at least very difficult to recover. The receiver battery will be a 4-cell 4.8 volt AA size pack, while the transmitter battery will be 8 cells [9.6v] – both Nickel-Hydride (NiMH). Orange, Red and Brown are the JR colour alternatives to the more familiar White, Red and Black of Futaba.The best supplier of Rechargeable batteries for models is Component Shop. They can supply either version of the coloured cables. If you don't spot the exact pack on their website then send them a couple of photos and they will almost certainly be able to supply you. The link is here **LINK**
Dave M