Train, heave on to Euston... - The Smiths

The company that runs Euston has a decent website for the station:
http://www.networkrail.co.uk/aspx/819.aspx

There is this about bicycle facilities:

Bicycles
Bicycle facilities are presently on the West Colonnade outside the travel centre

Contact them to get more info:

Address:
Room 430
Stephenson Room
East Colonnade
Euston
London
NW1 2RT
Tel: 0207 9226482

Let us know what you find out!