The alternative for 0845 161 0009 appears to be +31 20 850 1004 as they are both answered with the same IVR (recorded menu). Whilst you can use a call provider such as
1899.com to call this number, there is a UK alternative number which is to ring the main Tomtom UK office number, 020 7387 5444, and select option 1 to be put through to the same IVR.
Also, customer services in different languages:
+31 20 850 1001: Dutch (also +31 20 850 1007/13)
+31 20 850 1002: French (also +31 20 850 1006/12)
+31 20 850 1003: Spanish (also +31 20 850 1009)
+31 20 850 1004: English - as option 1 on 0207 number
+31 20 850 1005: German (also +31 20 850 1011/15)
+31 20 850 1008: Italian (also +31 20 850 1010)
+31 20 850 1014: English (this number worked on a Saturday!)*
* The 1014 number was open for Returns for Halfords only and not for the public! The lady wondered how I got through!