Lee,
The white over blue square is Royal Signals, the other one is new to me, As I cannot see a body on this K9, I would assume that it originally had a house-type wireless body. A lot of the K9's that survived in service the longest, were Signals vehicles, then when disposed of, the bodies were removed and put on the back of Bedford RL flatbeds, along with two 3.5kva gen sets.
Will see if I can find out any more on the other sign.