The info on the packaging is a bit wrong. You should prune newly planted clematis as suggested, to encourage lots of shoots from the base. However, C. montanas do not then need any further pruning, except to remove dead or unwanted stems. If you prune again in February you would have to wait another 12 months for it to flower. True you would get a lot of new growth for the future, so I suppose it depends on how long you are prepared to wait for flowers.

We prune our montanas regularly after flowering because they are so rampant. They often get pruned to three or four feet in June/July then may well require another 'haircut' later in the summer - very likely will in this wet one.

Maybe, but not in February, like C. viticella types.

No, definitely not February or no flowers.

Thanks folks !!! I think I shall just leave it be then and see what happens .. Thanks for your views :-)