I have found Coopers kits to be good.
the first kit I experimented with extra hops in was a Coopers Australian Pale Ale. 20g Cascade boiled for 20 mins in a large-ish saucepan, then another 20g added 'dry hopped' in a boiled muslin bag, dangled in the FV with a sterilised shot glass to weigh it down.
fantastic. Could've been even better if I'd boiled those hops in a bit of the wort rather than plain water but you live & learn!
Try festival kits. I made the porter for Xmas and it was awesome!
not tried that one but I have a "go to" recipe for porter which is (IMHO and that of the bass player in my band) excellent:
Brew In A Bag method:
21L batch size, OG 1044, FG 1011, Colour 43.6EBC, Bitterness 47.4IBU
3474g pale malt
509g brown malt
270g pale crystal malt
198g chocolate malt
100g torrefied wheat
mash for 90mins at 67degC in 28.5L of water (brewing liquor) pre-treated with 1 campden tablet to remove the chlorine from the liquor
after 90mins remove the bag from the boiler, drain the bag into a clean FV and then add that wort back to the boiler; bring up to the boil, then...
boil for 90mins
Fuggles 59g at start of boil
Fuggles 20g at 10mins from end of boil
Irish Moss 5g at 10mins from end of boil
fermented at 20-22degC with Nottingham ale yeast
I have a rather nice Chocolate Stout recipe too... c.f. Saltaire Brewery Triple Chocoholic...