I grew them a few years ago and as far as I can remember they are semi bush but did not need pruning and did reasonably well outside even in N E Scotland

I am also growing Marmande outside.They are for sure a bush and very strong.Lots of large good tasting fruit . I have not pruned mine.have picked the first 8 fruits which were hiding underneath the foliage,and really needed more staking because the fruits are so heavy. I think this is where 'cages' are necessary although I have never used them.I can see that this prolific. harvest needs different attention than the 'Firline' which I am also growing outdoors. I have always been very happy with the Firline previously,but they kook puny in comparison.
( I must contact Bertie! )

Thanks to Puddock & Justvera for those answers, just what I wanted.