The clay in LBC's is naturally a pink colour, so as it weathers the face colour changes. The colour does not go through on these bricks.
If you are changing a few bricks scattered around the wall it's more important to get the colour of the mortar right than the brick.
If you look at most walls the bricks vary a fair bit, but the mortar is the same colour.
When a few bricks have been replaced they really stand out if the mortar is really light. If anything a slightly darker colour of mortar stands out less in the wall.
They defo look like LBC Heathers to me. Bear in mind that heathers are normally not one shade - they are normally a mix of three or four. I was asked to report on an extension a while ago that was a different colour to the main house. The owner claimed the builder had used the wrong brick. In fact what had happened was the house owner gave the builder a single brick that was left in the garden by the original builders. The builders matched that brick - an LBC heather - but the extension ended up looking a completely different shade to the original house which was a mix of three shades.
Went to the reclaim yard today no luck....next stop Jewsons and you guys were right they are LBC Heathers, I just had to sort through some to find the lighter ones......Thanks for the pointer everyone.