War Pension,
Service Personnel and Veterans Agency
Telephone: 0800 169 2277
Crikey, that is well out of date.
SPVA became Veterans UK when it lost agency status and merged under the Defence Business Services umbrella back in April 2014.
The telephone number changed to 0808 1914218 back in 2018 to mark the 100th anniversary of the armistice that ended the First World War!