Have you checked for “known network faults”?
As well as trying the “check service,” Area status webpage" (link at top right of this forum), also try the “free & automated” Service Status number - 0800 561 0061 - which usually gives the most up to date info. and tells you of more local issues down to postcode level. These may not be listed on the Area Status web page (Areas are not “Geographic” they are billing areas) as that usually only covers faults affecting 1000’s of customers) so phone may give you more info, but even that wont cover problems affecting just a few customers.
And..... Is your device capable of getting speeds over ~100Mbps?
What is it (they)? And are you connecting on wifi or ethernet cables? If wifi - is that on the 2.4 or 5 GHz bands?
Of you havent- run speed tests on an ethernet connection.
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John
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I do not work for VM. My services: HD TV on VIP (+ Sky Sports & Movies & BT sport), x3 V6 boxes (1 wired 2 WiFi,) SH2 in modem mode with Airport Extreme Router +2 Airport Express's. On VIVID200, Talk Anytime Phone, x2 Mobile SIM only iPhones.