For anyone interested in such things, software version 5.14 has appeared on my 360 boxes. I only noticed it by chance Sunday evening. As per usual, the 'What's New' section is uninformative and there...
I tried a couple of the streaming apps yesterday evening - ITVX and All4 - for the first time since the update and was pleasantly surprised to find that both these apps that were previously slow to load and navigate are now more usable. Not exactly sprightly but certainly not the turgid experience they were before.
Info below from VM's /Digital-life/ page regarding the 5.14 update.
TV Guide for FAST channels
Our selection of FAST (Free Ad-supported Streaming Television) channels now show programming information within the TV Guide, enabling you to easily see what shows are currently broadcasting. More information on our FAST channels can be foundhere
Continue Watching
A show will now stay in the Continue Watching section if there is more than 5% or 5 minutes (whichever is lowest) remaining at the point you stop watching. Previously this was 10% or 10 minutes. This change will prevent shows from disappearing too early from the Continue Watching section