Box of 10 for under £4 :
https://www.ebay.co.uk/itm/382Y-P21W...1YLb:rk:8:pf:0
Can't really see them through the lenses, despite the fact the lenses are clear because they're diffused so reduces the fried egg look.
Alternatively you could go for orange LED indicator bulbs and dummy load resistors but the price is much higher.
https://www.classiccarleds.co.uk/col...5s-p21w-glb382
These allegedly don't need the dummy load resistor but worth a (free) phone call to check!