Updating maps for Binatone X350

Hi all. I want to update the maps for a Binatone X350. The set is about 3 to 4 years old. I have spoken to Binatone, who want to charge £32.50 to do this.
However, the guy I spoke to said you have to send the unit in, and it may take 2 weeks. He was also vague about how old the maps are, but said they should match anything yuo see on Google maps. I have to say I was not impressed by his service, and his very broad Geordie accent was hard to understand. (no offence).
The set belongs to my brother in law who is going away next weekend, so he may not be keen to send the set away for so long.

After speaking to Binatone, and doing some more search on the web I found a page on their website that says they update maps by sending out a SD card - which makes sense. (as the set has a slot). Maybe they just dont do that anymore, but the helpdesk is now closed (thats useful).

Anybody had any experience of updating this or a similar model ?