Well it is M stellata which is much smaller than grandiflora. Which way does the border it is in face? I am getting the sense that the main part of the tree is in shade for a lot of the day and the top part in full sun. If this is the case no matter how often you prune it will want to grow up to the light. Pruning can be done in mid summer when the shrub is in full leaf - have to say in all the years our has been in the ground we've not needed to prune at all.

Looks like magnolia Stellata, some of the magnolias when pruned can send out lots of shoots from the cuts, so you have to prune very carefully so as to not to ruin the natural shape, I have pruned many magnolias in my time, and the secret is to prune them slightly here and there over the years so as to keep a natural frame work, looking at your picture then I would take that top growth off to say the wall level so it does not look too large for the small border, Stellatas look better with this shape, then over the coming years you can shorten here and there some of the side branches, but don't over do it, done properly you can keep it to its natural form, I would carry out any pruning in May/June.

Thank you moon grower. So yet again another example of previous owners planting. Yes it is in shade for far amount of day. Don't know if you remember, it's like the whitebeam you suggested I remove last year as she had planted under our main electricity wires.. I did take your advice and get rid of it. Thanks again Jen

Good luck Jen, it would seem the previous owners didn't really consider where they planted long term shrubs and trees.

Sorry Julien, I didn't see your reply last night, thank you for your advice. Much appreciated.

Thanks moon grower, my next job is to take out a everygreen oak that is growing just along from the magnolia. They really didn't have any idea lol.