Plum trees - safe distance from properties?

Hi,

I'm currently helping two people with their gardens and by coincidence both have concerns about plum trees being close to their properties. I understand that 3m is the recommended minimum distance for a plum on dwarf rootstock on clay soil but I'd be very grateful for advice from anyone with more knowledge of this subject than me as to whether these two need pruning/felling.

1. 4-5yr old dwarf rootstock plum (owner is unsure of exact rootstock but def dwarf) Planted in a raised bed enriched with compost and topsoil, but presumably given the size of the tree the roots are now through that and into the subsoil? This one definitely needs a prune, but does pruning restrict extent of root growth and if so will a good annual cut back be sufficient to prevent to prevent roots damaging property?
Trunk is 1.8m from small front extension and 2.85m away from main building. Plant in the foreground is a currant bush, plum tree trunk hidden behind that.







2. 2yr old plum on dwarf rootstock, planted direct in enriched clay soil. I can't measure distance to the property accurately because of the fence but it can't be much more than 1.2-1.5m from property wall. Would strict pruning/espalier growing create an acceptably small root ball or is this one a danger to the brickwork/foundations if left in position?



If pruning is sufficient to keep these trees healthy and protect the properties I understand now is the time to do it - which I was surprised at as I am used to apple and pear trees which I normally prune in winter. Would you advise pruning now or waiting? With the first tree there is lots of unripe fruit on the branches so pruning now would mean losing some of this.

Many thanks for all advice, Andy