why do they only put one phone point in the house?
I think old habits play a significant part. For so many years (in both the U.K. and the R.o.I.) all internal telephone wiring was installed, maintained, and owned by the monopoly phone service (Post Office or PTT). Extensions were an extra quarterly charge, so many houses had just the single telephone point (and a single phone), which was typically located in the hallway.
In the U.K., the situation didn't change until the early/mid 1980s when internal wiring then became the responsibility of the customer, with BT controlling everything up to the NTE (Network Terminating Equipment, otherwise known to most people as the master telephone socket -- the first jack the line goes to after entering the house). I'm not sure exactly when internal wiring was deregulated in the Irish Republic, but I think it may well have been later, certainly into the Telecom Eireann era (predecessor to Eircom).
Many people still don't make provision for extra telephone outlets, even on new builds, so you'll often find a new house in which BT/Eircom has installed the master jack but that's it. I've often had wiring projects where the client has made out detailed lists about fancy lighting and so on, but it's not until I've prompted him about telephones that he realizes he's completed forgotten to make any provision whatsoever.
But back to the problem at hand.....
When we had a spark come out he told us to get another phone point we'd have to have Eircom come out and do it as it had to be rigged externally
Are you sure he didn't think you were after a second line rather than just another phone point?
It sounds very much as though he was thinking along those lines (excuse the pun). You could sometimes run extension wiring outside the house and back in again if it makes the job easier, but that would still be down to you to do, and the wiring should be connected to the network interface
inside the house. Extension wiring actually connected to the line at a box outside disappeared with the era of the Post Office/PTT monopoly.
I'm not sure if Eircom will still accept responsibility for extension wiring from older-style network interfaces, but I doubt it. They might carry out internal wiring for a price (with you still owning/having responsibility for it afterward), but it would almost certainly be more expensive than an independent telephone guy.
Do you have the current NTU 2001 style master jack installed? It will look something like this, with a removable lower panel (somewhat similar to the U.K. version, but it accepts American-style modular plugs):
The problem now is that if I plug the line that runs upstairs to the other Sky box (thank you, Spark), it kills the phone line, so that box is now not connected to the phone line, which I hope won't be a bother for Sky.
That sounds as though something isn't connected quite right. The Sky receiver should work perfectly well without a phone line connected, so long as you don't need to use it for those pay-per-view services.
A temporary solution until I get things sorted for the dangling kitchen wire.
By the way, if that extension to the kitchen is still connected (either directly into the back of the NTU or still plugged into the front), just exercise a little caution with the bare ends of the wires when you start trying to reconnect them. Although the power is limited, there is enough voltage on a telephone line to give you a bit of a bite, especially when it rings on an incoming call. Make sure kids and animals can't get hold of them too.
The only thing odd about how you have described your set up is that instead of terminating the extension wire in a connection box they plugged it straight into the phone.
Definitely a DIY job. The other difference would be the wire type. I'm assuming the wire installed is "flat" telephone cord for terminating into the modular plug. Fixed wiring to an extension jack would normally be done with round cable which has solid-core conductors.