Now the colder weather is here I am experiencing starting problems with my Transit van. I wait for the dash board light to go out then it turns over for ages until it eventually fires up. Would it be the glow plugs, if so are they easy to change, or can it be more involed. Comments please.

YES.

Yes, probably the glow plugs, yes they are easy to change, and yes they are cheap if you don't go to Ford for them, check out your local Motor Factor

With glow plugs it pays to buy a quality big brand if you plan keeping the van through next winter.

You can test them using a multimeter on ohms range. I used to have lots of them go on my renault kangoo. You should see a resistance between core and body of plug. Probably just one or two gone.

Turn ignition on, wait till glow plug light goes out, turn ignition off then on again to re warm the glow plugs this time start.
Usually starts much better but you will need new plugs soon.