I don't think that there is any special about planting them, O. They are small tubers and just need planting. They are climbers so need a bush/ hedge or something to climb up. Given the traditional Irish climate they should do well for you.
Speaking of Tropaeolum speciosum, we haven't grown it for years yet, when weeding the other day, I found three small ones growing beneath an acer. I don't know how they got there, do they put seed in bird food?

Bulba - is it possible there were some tiny tubers left from your old plant which have now grown big enough to produce shoots?

You may not remember Bulba....but you managed to identify this plant which is growing up through my privet hedge in the front garden. I managed to find 8 seedlings around the garden. I potted them on and they all died :((( I'm hoping to get some more this year and try again.
Any advice Bulba or Andrew?

Scottish, it seems to be one of those plants that either likes you or it doesn't. Some gardens just cannot grow it whilst in others it can become quite invasive.
It is many years since we last had it, Andrew, so it don't think that it is a remnant of the original. In fact I am now questioning my id of it. Having lifted the plants yesterday I find that the roots are more fiberous than I would have expected. The seedlings are now safety captive in pots and I will see what they grow into.

If I get anymore seedlings this year - I'm going to leave them where they are for a while and let them get stronger before I attempt to lift.

I wish I could give you some ideas Scottish. The tropaeolums seem to be a perverse family. I am growing T. polyphyllum quite happily but cannot get T. tuberosum to show a shoot above ground, despite several attempts

Thanks andrew...I'll persevere with this perverse bunch :))))