Where is your clematis planted, Bredakelly? They like to have their roots in the shade and are very greedy feeders. You also need to plant them very deep, so that they're less prone to clematis wilt. Has it grown many new leaves this season? Does it look droopy, as though it's dying? If so, it could be clematis wilt, especially with all this damp, warm weather we've been having. Key in 'Clematis wilt' on google and see what they say, or they may have some pictures. If it is this, you may have to cut it back nearly to ground level, and just hope it will throw up some new shoots after a while. This happened to one of mine a few years ago, and it did grow back, but not all of them do. Good luck with it. Annie (Cumbria)

I checked back for your original question,Breda, some weeks ago now. I note you say the leaves were 'speckled' with brown - has that improved, or got worse? And are the 'speckled' leaves distorted in any way?
I also note you said you were feeding it tomato food - I hope you are not still doing that. This is not a suitable feed for this plant, being very high in potash - what it needed was a balanced all round feed such as Miracle Gro General Purpose - this will contain enough nitrogen for good leaf growth, and enough potash to encourage flowering. That said, any feeding now should be stopped, it's too late in the season, and next year, a handful of Growmore or Vitax Q4 at the base of the plant, lightly forked in, will be sufficient for the season, they do not require feeding all the time when in the ground.
Note also that this is one of those clematis which needs to be cut down to 2 pairs of buds from the ground in winter, by mid February.
Secondly, this plant produces flowers from mid summer through to mid autumn, though clearly, yours isn't at the moment, but I note the label said it was in flower all summer, which it isn't. I'm interested in quite where its planted - in sun or shade? How close to the wall or fence behind, and how close to surrounding plants is its root ball?

You have told me that its planted 15 inches away from the fence, and that there are no other intrusive roots from other plants nearby, Breda. Also that you've stopped feeding it tomato food and did give it miracle gro, and will now stop feeding altogether.
Only other thing I'd suggest is perhaps plant some ground cover or a low plant in front of the clematis, if possible, to provide a cooler root run for the plant.

I have over thirty clematis plants and two are, Duchess of Albany, one having been here for a few years, the other, bought last autumn. With the old one I never fed it and it rarely got any water. It thrived in our Zone 5a climate in Canada, going down to -20C at times but good snow cover. However, when I moved it, it hasn't been as happy as its roots are in the sun. It still blooms and this year will have much shade on roots.
My new one is in my secret garden, roots in shade and it will head to the sun.
Our soil has had years of cow manure trenched into it so that is probably why the lack of fertilizer did not matter.
I read that one should feed in spring once the leaves start, but before flowering.
I am not an expert, just a clematis lover.
If you are prone to clematis wilt, I suggest to stick to the Viticella varieties as they are not prone to the wilt.
I have some magnificent ones, Betty Corning, Julia Correvon, Polish Spirit and Venosa Violacea.
My favourite of the Group C (3) is Perle d'Azure which has never been a problem and every time I moved it, another came up from where it had been. I now have four, all from the one plant. Jackmani is also easy to grow. I believe the Texensis group are a little more difficult. Raymond Evison has been my guru, in books, over the years.
Marie Boisselot, a Group B does well for me, white, prolific and takes what comes, no water and no food and still thrives. I must add, that we have twenty acres of land, three acres of garden so have a lot to look after, hence some plants not getting all they should. The strong survive here.
Maidwell Hall does well for an early clematis in spring. Lots of green for the rest of the year. It layers itself and produces more plants. Again, not much care given. It can grow very large here.
Clementine