Hi mate, painted loads of landys and my dads old champ twice.
For a champ you will need 2 litres of top coat, I buy my paint from the local motor paint supplier, synthetic, that way you can put it on top off anything.
I use short pile gloss rollers(£5 for 2 from b&q).
You will also need a good brush for the fidliy bits.
As for primer, ive never used it!, just rub down old paint well and put top coat straight on. However, if you want to use primer, red oxide/grey coulour will do.
Hope that helps.