Standard release blue peaks are virtually non existent and always seem to go quick from retailers so surely a sealed beam version plus a 45/1 would fly off the shelf!
Barring the lucky few that managed to get hold of either 45048 (one went for £245 on eBay recently!) or one of the bodyshells Bachmann sold off they very rarely come up, and also aren’t very common on a lot of 80s layouts I’ve seen either.