LIS/MAD
One would hope that both IB and TP are very high (if not at the top) of Mr New Route Development guys list for BHX. My cousin flew BHX-LIS almost weekly when WW started it and said that flights were nearly always full (although we have no idea what fares people were paying and it was dropped pretty sharpish in their city route cull in 2010). As chinapattern says, with some connecting traffic thrown in, it could work for TP.
I wonder how IB are doing from GLA, I see that it is only twice weekly (Tu/Th) so must be relying on a lot of connecting traffic as can't see a lot of bsuiness travellers being attracted by that schedule? Surely BHX could manage a four/five times a week rotation?
IB and TP are daily at MAN (for the summer only in IB case), I recently flew IB MAN-MAD, both flights were full on a CRK. I agree that there is definately potential for both carriers and any deal sealed on these would be a huge boost for BHX and its already healthy list of legacy carriers as well as opening up South America, which for now requires slight back tracking via AMS, CDG, ZRH or FRA.