Explorer Indicator (turn) tail light bulbs

I own a 1998 UK spec (european model) explorer. I have since bought a set of US spec clusters for the tail lights (not available in the UK). My problem lies in the fact that red turn signals are illegal in the UK. I have removed the red lamp sections from within the units and am looking to simply fit orange bulbs.
However my explorer has multi blocks with spade type fittings for the bulbs ( my haynes manual shows that the bulbs should be standard Round bayonet fittings). Two problems the spade type bulbs available from ford in the UK are only supplied white and not orange, plus ford want around £4.00 (nearly $7.50) for a single indicator bulb.
Does anyone know if multi blocks that will fit the standard wiring harness plus fit the tail light unit and that have a round bayonet bulb fitting can be obtained or if they are made at all.
Any help much appreciated.
Thanks,
Neil...............