Only problem I would see would be tying the rose to give it some support to stop it from falling to the ground. If roses already grow in your garden there's no reason why a climber/rambler shouldn't succeed, always allowing that your not planting too close to the established roses.

As to which one, there are so many - pck a favourite colour and go from there. Good rose suppliers are Beales (Norfolk), Fryers (Cheshire), Austin's (West Midlands) or closer to home for you Gandy's in Aberdeen - I'm sure the Scottish gardeners here will have they're favourite suppliers.

ps Gandy's website has a really neat rose finder database that lets you select by colour, fragrance, type and, if you're interested in the history, by the year the rose was bred.

don't forget the winter clems like C cirrhosa and C repens 'winter beauty'.

Remember to feed the area though as the tree will have impoverished the soil somewhat.