Nuvi 310 problem

Whilst travelling in the UK last month I purchased a Garmin Nuvi 310,
needing only the UK maps at the time.
On returning to Aus, when I could connect to my PC I discovered that
the 310 had a text to speech feature.
But when I go into the locale menu I have only the American/British
English to select from, and no TTS voices.
In the voices directory on the Nuvi there are no TTS voices either.
I installed the CityNavigator maps for Aust. but with no change.
Thinking that perhaps I needed to upgrade the Nuvi software I
downlaoded the WebUpdater from the Garmin website and ran it. It
updated my unit to version 4.10, but my Nuvi now tells me it's a Nuvi
300!
The latest software for the 310 is actually 3.10.

Two questions please, how can I get rid if V4.10 and upgrade to V3.10
and restore my Nuvi 310?
How do I access TTS?

Any suggestions appreciated.
Mike

1. Try the manual unit software update file for the Nuvi 310 rather than
using the WebUpdater to restore its Nuvi 310 status. After than you should
be Ok again.

2. Only the Australian/NZ Nuvi 310s have text to speech. US and European
units don't. I think the reasons is that Australia doesn't get the 350/360
models and without them they wouldn't otherwise have a TTS option in their
Nuvi range.