Well, I live in Southport and like to shoot airshows, so it would be pretty odd if I hadn't done my local show. 
Having said that, whilst it is a nice show and you are right the sun is nicely positioned for most of the event, I don't actually go most years.
However, the reason probably won't be an issue in your case.
The main reason I don't usually go, is that it isn't as big as some shows and the participating aircraft are "the usual suspects" that visit most airshows, and I have plenty of photographs of them all already. I have actually driven all the way to an airshow at Duxford on the same day as Southport airshow (about £60 petrol for the round trip plus a quite steep entry fee) because of the better selection of aircraft displaying. I will only now go to Southport airshow if the weather is perfect for photography (blue skies and fluffy white clouds), although I will tend to sit out in my garden and watch the aircraft from there.
However, as you haven't been to an airshow in 30 years, all the aircraft will be new to you and it is quite a nice place for photography (aircraft passing over the pier for example). I would think you would enjoy the show, and get some great shots. Yes the Vulcan is awesome, both in sight and sound (I have seen it performing at least a dozen times now at various shows). The Red Arrows, Typhoon, etc., all put on really good shows, the Tornado display with simulated ground attack mission and pyrotechnics is great, it's just that I have seen them all before many times so have got a bit jaded.
The BBMF can be a bit hit and miss as to what might actually turn up on the day. They are very fussy about weather conditions etc., with the Lancaster and won't fly it if there is too much wind, and for some reason (considering the budget they must work with, compared to many of the privately owned WW2 warbirds) their aircraft tend to "go tech" quite often (i.e. have technical problems which ground them on the day). This means that it is by no means unusual for one of the three to be replaced by the teams Dakota (which is pretty bulletproof and flyable regardless). So, you may not get the 3 ship formation you want.
If attending, I would recommend the beach parking and get there early to get a good spot near the flightline. That way, you can hang near your car (and coolbox, food etc) if you wish, with a bit more space. It is also worth taking a small set of steps, one of those three step jobs, that can also double up as a seat. Very handy for climbing up to shoot over the heads of those who are packed in tight along the edge of the flightline. Although the main event doesn't start until lunchtime, there is entertainment during the morning (radio control aircraft put on a quite nice show for example).
For somebody who hasn't been to other airshows recently, it should be a very enjoyable event though.
