Got home & speed has crashed

[#1]

Got home from work and find appalling speed on my router, which is generally left on.
Can this be nudged please??; never had such a low speed of 768kbps upload

[#2]

Have you tried a resync - it should a lot higher assuming your default noise margin hasn't been increased to 15dB then another during daylight hours to get it back to full speed
Note that Plusnet can't nudge your sync speed other than with a line reset which isn't a good idea usually
Further note - The speeds have been like that for about 31 hours according to the router stats

[#3]

Thanks Old Jim; must admit hadn't noticed how long it had been that low