Welcome Gareth. There are a lot of us returning at a more.......experienced age
1/24 really is large scale and to be honest there are very few kits in that scale. The old Airfix 1/24s are not bad but things have moved on.
The most rapidly expanding scale in terms of choice is 1/32 and the most popular is probably 1/48. There is a lot in 1/72 but that's on the small side, though it's also cheap
As a general rule newer mold kits will be easier to build than old kits. This is simply because the technology has moved on, both in terms of drawing and cutting the molds. It is a bit of a minefield because old kits are often re-issued, sometimes under different brands, re-boxing as it is known.
It's not really possible to single out a particular manufacturer as good or bad. All have some dogs and most have some very good kits too. Airfix are still going strong and some of their new kits are very good indeed. The older ones are sometimes more of a test of your technique!
All the mainstream manufacturers do some good kits. Revell of Germany (RoG) are usually good value for money. Tamiya and Hasegawa make some good stuff and more recently the Chinese in the shape of Trumpeter and Hobbyboss have produced some good stuff. There are others of course.
Before investing in a kit it's always worth checking online for reviews, though bear in mind they are not always unbiased. You could also do worse than asking here. You may well find that someone has already taken a swing at it and can give a genuine modeller to modeller opinion.
I would advise against attempting more specialist, limited production kits until you've got your eye in again. These can sometimes require a bit of fettling (to put it politely)
Don't forget that if you've got any questions you'll find a friendly answer here.
Cheers
Steve