Andrew,I use a straight lead usually about 3 oz, with hook length of about 12 inches tied to the main line about 18 inches above the lead, very simple and straight forward, main line about 8lb, hook length, about 6 lb with a size 6 wide gape hook, the flake just nipped around the hook as you would for Chub, I also use bread paste which is really just as good.
I just lower the sinker down the edge of the harbour wall, let it touch the bottom, then wind in a couple of turns so you get a bend in the tip, the mullet really can be very frustrating, sometimes they just give a hefty tug , sometimes they nibble, and twitch at the bait for ages.
For attraction, I use a cheap loaf, torn up into bits, this is put in an old landing net net with a string through the top, I put a weight into the net and lower it to the bottom on a rope into the water about 6 feet uptide of the hook and bait, give the net a shake every 5 mins to release bits of bread into the water.
Very basic and simple really, you need a drop net though if you are any height above the water.
Dont drop your hook length bs too much, those Mullet can give quite a fight and are not line shy when fishing in a tidal area, if you try for them in a creek or still harbour though, thats another matter entirely.
I shall be down in Padstow after the Mullet ( and Bass ) at the end of this month.You can float fish for Bass of the same harbour wall using frozen Sandeel.
Good luck.
Dave