Couple of questions - what part of the UK are you in? Is the situation very exposed and open, meaning it can get pretty windy/cold in that area? I'm already assuming that this wall you have planted against is large enough to take a plant that will eventually be 12 feet wide by 35 feet high... if that's not the case, then some idea of the area size would be useful, together with info regarding what type of support you've erected on the wall. Or a photograph...

As Bamboo says, this particular Jasmine gets absolutely huge, so you may want to have a rethink and replace it with something less vigorous. The RHS website will provide you with some workable alternatives.

Thanks for your responses.
I've added a photo now, and the variety is Clotted Cream.
The wall is confirmed as east facing.
The location is Merseyside, North West, quite close to the sea which is to the west, about half a mile, so westerly winds are salty sandy. But easterlies are not.
Soil is light sandy loam, but home produced compost added annually.

Ah - if its Jasmine 'Clotted Cream', that's a smaller plant, gets 3 x 3 metres - but, and this might be the problem, its listed as 'frost hardy', which means it doesn't like winter cold at all, and this fact might mean that, although yours hasn't been killed by cold, its certainly been checked by colder temperatures in winter. You may want to leave it in situ to see whether it gets larger over time, given the mild winter we've had this year, and particularly as you're not far from the sea, which means temperatures are higher than inland in winter. But there is one thing I'd check - if you've planted it less than a foot away from the wall, that's too close to the wall, it needs to be repositioned to leave at least a foot between it and the wall, so that it's not suffering what's known as 'rain shadow', meaning it doesn't get enough moisture on its roots when it rains.

Update - I've just checked out the photo you've posted, and that plant is too close to the wall. It also appears to be beneath a window, so seems you will need to keep it clipped back in that area if you replant it in the same position, just further away from the wall. I also can't see any kind of support in place, and that's something you really should erect before much more time goes past... best to choose the fence panel type trellis sections because they're strong enough to hold the weight. The folding, criss cross trellis always breaks...

The other option is Trachelospermum jasminoides - it gets larger, more than 4 x 4 metres, is evergreen, has fragrant flowers with a scent similar to Jasmine, but it (like Jasmine) prefers full sun and a sheltered position - it is, though, hardier than your Jasmine - listed as hardy down to -10 to -5 degC.

Excellent reply, thank you for the help.
I things that the sap is still dormant so we are in time to replant now, and get good compost down to the roots, and maybe a waterhole hole as well, similar to a clematis planting.

Good time to erect a support too... before it gets going! And a little tip if you want to fix a trellis panel to the wall - fix the horizontal supports to the wall, meaning the vertical struts are on the outside, so the plant can twine round them, upwards. Try to get the roots out intact, or keep a good solid rootball in place when you dig it up...