I am thinking of upgrading my Digifusion pvr to a Humax HDR later on in the year, although judging by the comments I have seen so far, I am beginning to wonder if I am doing the right thing, especially after nearly five years of relatively trouble free viewing.
As I have an HD ready TV, I thought this may be as good a time as any to improve on the performance.
I still have a sky dish and cable installation from the days before sky started rocketing the prices, but I just need to know what if anything has to be changed on the dish such as the LNB etc or, should the Humax work straight out of the box?

"... the days before sky started rocketing the prices". Well now, I remember Sky Sports going from £5 pm to something like £20 pm in just a few years. That was back in the analogue days and such a dish will be pointing in the wrong direction. It could be realigned but the LNB will be old and maybe not as sensitive as recent ones so it might be worth starting over with a new dish. If you are referring to more recent Sky Digital price hikes, the dish should be fine although you may only have a single LNB (only one cable into the house). The HDR will work with that but there will be limitations as to simultaneous recordings. If you want full functionality from the HDR, you need a quad LNB with two cables running to the box.

Right, thanks.
The dish is a mini dish and judging by the direction of fairly recent installations in the locality, seems to be pointing at the same spot in the sky.
Still, if it means new LNB(s) and more cabling then it’s beginning to look almost like a new installation.

Swapping the lnb for a quad is a simple 5 min job and then all you have to do is run a 2nd cable.
Quad lnb's can be bought on ebay from about £20.00

Oh right,
Well that seems straightforward enough, and rumour has it that it’s possible to buy, obtain, use, a two in one cable instead of two separate cables. Any idea what type this is or it’s possibly a Maplin item?

You can buy "shotgun coax" - essentially two pieces of coax joined side by side - assuming that#s what you mean?.

If you mean feed two LNB feeds down a single cable, that's called a stacker/destacker, and isn't cheap - and makes a fairly high loss as well.

Yes, that seems to be the one.
As I am having some work done round the top of the house, it seems logical to have a neat cable put in at the same time, especially if there is no detriment to the signal using this type of cable.

Standard 'shotgun' is just twp pieces of normal (what used to be CT100) coax joined together. The very thin shotgun cable that Sky installers uses makes considerably greater losses, so is best avoided.