Tonic Please
A little follow up - I have a Realistic Pro 2004 ( same sort of coverage as the Icom but non-portable). For a permanent, internal installation I made a discone aerial to a pattern published in a magazine some time ago. Very simple to make - a sheet of card (A1) some kitchen foil and some co-ax to a BNC. Very wide band - 100Mhz to 1000 Mhz.
The same article gave instructions for an external version which was almost as easy.
I note your location and since 'CJ Towers' is in Addlestone, if you would like more info, e-mail me.