Well the red flowering plant looks like the hibiscus, it looks ok. Lady Di creeper? From your description sounds like a Mandevilla, is that right? If it is, after about 3 years they do tend to loose their lower leaves - I think they consider they don't need them. And they do start to look a bit ratty. Also they can suffer badly from sap-sucking scale insect. I've had a few in for around 8 years and after about 4 or 5 years they do become a bit bare on the lower stems and the flowering gradually drops off. Fertilising helps a bit but I reckon you're better off replacing them. That's if they're Mandevillas.

(The're not mandevillas, FW, it's the common name of the white form of Pandorea jasminoides.) Unfortunately however this is also a somewhat leggy-growing woody vine, and given anything to grow it will head upwards at the expense of lower growth. You may find some natural branching but really the only way to encourage new growth is by cutting back.
I appreciate what you are saying about doing so, and losing your pretty fence-top growth. Also you may well set it back as you would really need to go low.
There are a couple of alternatives.
You could try alternating the cut-back - leave some top growth and just cut back a couple of stems from each one down low to see if that stimulates new shoots, and then try to keep the new growth nipped any time you see a node, to promote further branching. Then a light trim after flowering as they seem to flower from the ends.
Second thought is to buy another 2 or three and bung them in between the others, but keep them pruned harder in the first few years so you get a bit more shrubbiness lower down
Thirdly, go for a cheat and grow some annual vines that will not take over but will produce some show lower down and also can use the stems of the Lady Di to grow up (this should not do any harm to your vines), I could suggest quite a few but some things are considered a bit weedy depending on your area and also you don't want anything too vigorous in growth or in self-seeding.

Thanks for both your replies funnelweb and alisonoz, Always helpful feedback. Yes alisonoz it is definitely a Pandorea and very woody. I really like the idea of planting some new climbers inbetween and keeping them low so as to cover the fence but still have my Lady Di's sitting pretty at the top! I used to have a ciimber that was very dense at the base but can't remember what its called so looks like a trip to the nursery (what a shame!! ha ha). Thanks again:)

Opps, sorry about that, should do a bit of research sometimes before responding to these questions, I had heard of it but misplaced its proper name. Josephine, there is a double form of the vine commonly referred to as 'the Blue Pea', which is in fact clitoria ternatea. It's not as rampart as the single flowering form and I've never seen it in a commercial nursery but occasionally you can find it around the craft/ farmers' markets. It has a lovely deep blue double flower; growth to ground level and will contrast with virtually any other flowering climber.

After all that it's gone! I bit the bullet and decided the only way was to remove the Lady Di creepers (all 6 of them). Shame to lose that big show of white flowers but in the end I think it was for the best. I've now taken away all the lattice and have planted 6 Syzygium Cascade (Weeping Lillypilly). I'm going to trim the sides regularly so they grow up to cover the whole fence but not outwards. Bit of a skinny hedge if you like (approx. 400mm wide). This will be a challenge but I'm up for it! Happy gardening all - its that time of year when I can't decide which area of my garden to work on first as there's lots to do, ha ha

Good luck with it all Josephine, keep us up to date on how it's all coming along.

B.

Thanks B, I sure will:)