The 2700HGV is an ADSL modem/router combo - it does not incorporate a base station for a BT cordless phone.
However, you can connect a wired phone (or cordless phone base unit) to the 2700HGV via the supplied adaptor to use on VOIP services. Land-line access can still be achieved by dialling an extra specified digit before the landline phone number.
In your case - you would need a new cordless phone if you move to either the Home Hub 3.0 or 2700HGV.
I have found the 2700HGV to be a reliable router operating well on my long line back to the exchange. It runs much cooler internally than the more domestic brands - i.e. Linksys, Netgear, Belkin, DLink, etc.
I have no experience of Home Hubs.
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Zen 1760/448k ADSLmax