The curious thing is a lack of a longer version, maybe cutting internal storage to 2 per bay on JSF, but delivering either much greater range/endurance or a much larger warhead......
RAF has/will shortly have exquisite, but limited Air to Ground munitions: Brimstone, Spear, Paveway IV and Storm Shadow. All highly precise...all highly expensive. We desperately need some SDB1, APKWS or JDAM equivalents in terms of cost.
You could go down the route of buying MBDA SmartGlider Heavy but you're going to spend a fortune on integration costs alone and to be honest it just looks like a warmed over HOPE/HOSBO with no modularity. I think the more sensible route would be to stick a wing kit on Paveway IV, or just buy JDAM-ER or Powered JDAM in 1,000lb form (although for the latter I'm not sure it would fit internally in the B variant). JSOW is another good weapon...but its not cheap. The modularity is great though.
I've long been a fan of just buying 1,000lb JDAM for Typhoon and F-35. Someone else has paid the integration costs already and its cheap as chips...but its not a UK made weapon. But I just don't think we can get as cheap without the US' immense production volumes.
Another option is to exploit the Spear 'shape' across a number of versions, which we're doing. But then create a larger 'shape' like JSOW that can also be exploited in a similar manner with multiple versions/payloads available. Saves a lot of time and money on integration efforts and enables re-use of components from within the Complex Weapons portfolio. Obviously Spear is the best example, but look at the JDAM family. 500, 1000, 2000lb bombs, Wing Kits for the ER variant, powered variants with wing kit, QuickStrike sea mines, QuickSink anti-shipping guidance and fuzing, Laser JDAM guidance...a whole host of capabilities from one simple initial design, that re-uses existing components either entirely or en masse.
Although we like to talk about 'Spiral Development' and modularity, and we are getting there with Asraam/CAMM, Starstreak/Martlet, Brimstone and the Spear family....the real masters in the past have been the US. But even the US has got there more by accident than design though (they've never really fully exploited the JSOW modularity and shape for example) with plenty of very sensible systems not making it to large scale adoption over the years (Sidewinder Sidearm, Sidewinder Focus etc.) and some that have made it essentially being lash ups, or gap fillers that end up serving for years longer than they should (Chapparal).