I picked up an old imperial swinborne socket set a while back on ebay for £80 and a box of imperial spanners from a car boot sale.
I find the quality of older tools far better unless you're buying high end new stuff.
Well done for finding those. Good old British manufacturing. These were the sockets to buy in those days of old. I still have my set of Swinborne sockets that i bought when i was seventeen (1978) and use them daily. all my other tools are mainly snap on though.