You could try a climber like the one in my front garden, dorothy perkins[pink] see my pics, i have this in the front garden spilling over the hedge, i have left it to go a little wild and is at the momment climbing through the canopy and beyond of the large stagshorn.

I don't want to be a party pooper, but the chances of a rose climbing 'through' a holly are remote - holly is evergreen, obviously, and usually forms dense foliage, so I doubt any rose will attempt to go 'through' If you still want to give it a try though, think about whether you want a rambler or a climber - ramblers tend to flower in one major flush, usually around June, after that, only a few sporadic flowers may appear if you're lucky. Climbers should be repeat flowering, and the pruning regime is different for both. Dorothy Perkins is a lovely rose, but it is a rambler, not a climber. Some climbers/ramblers are more suited to clothing a trellis or arch, others make large growth on large walls, so again, growth habit and extent of height and spread need to be considered.
Cecile Brunner is a good choice of climber for growing up into trees - its drawback is there's usually more foliage than flowers, but it does have an impressive flush of flowers in June, and sporadic flowering later in the season. Madame Gregoire Staechelin is a sight to behold in flower, scented and a climber, reaching up to 20 feet - its drawback is again that, despite an impressive flush of flowers in June, the flowering season lasts only a few weeks - it does though, produce rather noticeable, large hips.

Thanks to you both for your suggestions. Looked them up and they all look beautiful.Thank you Bamboo for your thoughts re climbing through the tree. The holly tree is very large (about 50/60ft) and the neighbours have agreed to have about 3ft taken off!! It does block a lot of the evening sun off the garden but it looks like I just have to live with it. So thought it may be worth trying to get some colour into it. Would I have the same problem with clematis?
Polly

No, you wouldn't - that will climb the holly tree by clinging on with its petioles, all over the surface foliage. Not sure I'd choose a species variety (montana for instance) because its not usual to prune those, and they can get 30 feet and will look like a lot of dead wood all over the holly in winter. Varieties are probably the way to go - if you choose one from the late flowering, viticella group, that gets a good size (Clematis Betty Corning, for instance) you can cut those down by midwinter, or at the latest by mid February, so you're not looking at all that dead stuff. Even if you leave something like Betty Corning unpruned so you can keep the height, it doesn't make really thick wood like Montana - but you will have bare stems up to the first 5 or 6 feet of growth.

That sounds like good advise Bamboo. It is a lovely clematis. Would the Etoile Rose clematis be ok also.

Yes - but it only reaches about 10 feet in height.

Thanks bamboo . I have been on the phone to my local garden centre to see if they can order them for me. Not sure about ordering clematis on the net.

I wanted Betty Corning earlier this year - couldn't get it anywhere, so had to give in and order it over the net - wasn't all that thrilled with the plant when it arrived, but it has grown on perfectly well. I think the member called Louise on here has a blog about internet suppliers of plants, ones she's used and who've proved to be good, might be worth finding that and reading it to see what she says about Clematis suppliers.