This is all you need (note the end chopped off the runner as it was too long), some spray adhesive (I went for carpet adhesive), tape (I used B&Q own brand 'high strength gaffer tape' as it's a strong adhesive), a sealant (which I ended up not using!) and some drop cloths to protect the floor.
Step 1 - Measure the width of fabric you need, remember to allow a good few inches either side for the fabric to fold underneath. Then cut to size. I was doing all this in the hallway and going through into the office, as it's the longest stretch of uninterrupted floor that we have.
Step 2 - Cover the whole place in drop cloths and lay out your rubber matting or rug or whatever you're using as a base. You might also need to curse at the doorway and try to find another area to do this, fail and decide to just move the rug once you get to the door or do this thing in two halves.
Step 3 - Line up the fabric and leave enough over at the start to fold underneath.
Step 4 - My technique was to then fold the fabric back into a loose roll, stick the first part down, then just keep spraying the rug and the fabric in sections and unrolling, smoothing out as you go. The pictures probably explain it better!
The carpet adhesive stuck together instantly and was dry in only 15 minutes, so it didn't leave room for error, but also that was good as it meant when I got to the door I could fold the start end up as it was dry and pull the rug through into the hallway and not have to try to negotiate the doorway.
Step 5 - Leave the adhesive to dry, then flip over. It's a good idea to use a fresh drop cloth, as you don't want to get carpet adhesive on the front of the fabric, and that stuff gets everywhere!
Step 6 - Fold the edges over and stick them down. Make sure they're pulled in tight and the edges are all even.
Step 7 - Edge the fabric with the gaffer tape to make sure it's really stuck down.
So here it is!
There is one more step, which would be to coat it with the poly finish, but I remembered at this point that we have a fabric protective spray (for car interiors) that would maybe be better as it's made for fabric. So Tom gave it a coat of that and we'll see if it does the job. It doesn't make it wipeable like a coat of poly might but it should stop it getting stained and doesn't make it shiny or 'crunchy' feeling as I was worried a sealant might. If it does start to show any signs of damage or staining I might give it a coat of spray sealer as well. So far it's stood up to being walked on, clawed by the cats a bit (although they got shouted at for that!) and even a bit of cat puke which seems to have come off ok.
I'm planning to make a doormat for the kitchen with the rest of the fabric and the part I chopped off the original rug, so will probably seal that one as it will be for actually wiping feet on.
I'm so happy with it and surprised at how easy it was to do once I had all the materials, you can feel the texture of the original mat underneath but it's just like walking on any rug as most have some kind of weave or pattern.
The budget breakdown is:
Fabric - £35.96 (4 metres of 'Autumn Leaves' from here)
Gaffer Tape - £5.98
Carpet Adhesive - £5.98 (I bought 2 cans just in case but only used one)
Pink rug - Free :)
Dust sheets (3 used) - £5.94
Total - £53.86
So I've got a 4 metre runner for under £55, I didn't count the polyurethane spray into that total as I didn't use it (and will use it on other projects so it won't go to waste) but even with that added on it would be under £60!