The connection you have is to go directly on to copper pipe, the issue you have is a lack of length and the isolator valves are there.
There are other connectors but you will be faced with other problems, like removing valves and having to turn all the water off if you get longer hoses.
What you have is fairly normal and would be resolved by buying a bit of pipe and extending it as described by the other guys. As you do that you will probably be thinking 'this plumbing lark is not as straight forward as I expected, Two trips to the merchant, hours wasted, nobody told you what to expect/the merchants only had one option on the shelf/no time to wait for a better part as someone want to use the sink/got to fix it today as too much work in tomorrow/had to buy an extra tool. This is exactly what happens to us every day, you just live with it so when you have completed the task and work out how much is should have cost at a minimum of £25 an hour/parts/fuel etc you can go back to your day job and tell everyone you know how it really is for us, jobs take twice as long as expected, parts need to be got, the unforeseen always crops up and things cost money. You can take pride in the fact you are the start of a new national mood where people appreciate plumbers and heating engineers as opposed to complaining about prices/time keeping/having to get parts. Be thankful you have not had to connect onto old imperial pipes, you have access to the pipes and you house does not stink as many of our lovely customers do. Don't forget to account for the 50% tax taken off us too. (Vat+income+nat.ins+fuel duty etc)