I can achieve 300kBps easy but it will knock streaming, gaming, VoIP out of use so I can only upload at 100-150kBps so my other services will still work adequately.
That's normal TCP/IP if you saturate the uplink on any service, you stop the ACK packets working for the other streams. If you have a router with QoS features you could limit your uploads to ensure that the tiny ACK packets get through whilst your upload runs at 280 or 290 kbps. This has nothing to do with Virgin at that point.
My main reason for wanting FTTC is so the upload has more bandwidth and isn't shared with local community...... (Local Loop)
If you have FTTC with 80/20 and you upload at 20mbps, you will still stop downloads working reliably.
One thing I do know about my local community is that many torrent constantly and don't understand anything about bandwidth or broadband what so ever... So they don't restrict there uploading so as you said such a small amount of upstream bandwidth being shared with many here as ADSL is only available and is around 1mbps so most are on Virgin and can really rock the boat.
They shouldn't need to, why does the general public need to understand TCP/IP ? Surely the ISP should sort this out. One house should be able to upload at max without affecting others; its a limitation of HFC networks (Hybrid-Fibre-Coax) which isn't a problem with twisted-pair/fibre networks.
So the network is being run close to its limits again.
They are locked in a marketing battle with the FTTC ISPs. Headline speeds are virgin's weapon, rather than quality. The fact they all market 'fibre' to the home is the main problem, nobody is told they are on a shared system.
The FTTC and ADSL ISPs have better effect sharing at the DSLAM/Switch level, rather than Virgin's sharing at the coax level.
James BT Infinity 2 19/09/2012 - Sold 42/6, Now 52/9, Sync @ 55 / 9.5 Mbps @ 470m approx
15 years broadband (1999 ntl: cablemodem, BT FTTC) - Router: Asus RT-AC68U (merlin) - Modem: HG612 unlocked Typical speedtest