Where to get parts plz.

Hello Dean,
Your first port of call may be Dave Hemsley details on this forum, who is the spares guru for the club and will have the seals for your diff etc, there are two sizes you may choose from and Dave will explain which one you may need.
The headlights are quite difficult to get hold of as they pop up on ebay occasionally, a Mk1 Capri and I think the Hillman Hunter also use the same lights so have a look around.
Dave may have some in stock, I have a spare one if your stuck which I paid £20 + postage a couple of years ago then a week later I saw some for £10 each but that's life.
Another good contact is Joe Mason in Worcestershire who is a three wheeler specialist who has gone to full time mail order for spares and has refurbs at a reasonable costs may be worth a call.
And the last one is Fifers Spares, as I said you may have to shop around a bit.
Your windscreen seal can be purchased at one of the shows eg NEC etc as they have all seals and rubbers for most makes of classic cars when we get back to normal, if your not so much in a hurry.
Best of luck with your searches.
Dave