Another idea.
Let's say the RAF had a bit more money, so when they retired the Tornado F.3 from the air defence role in favour of the Typhoon, they didn't just scrap them, but adapted some of them to two other roles:
1. Defence Suppression.This role was trialled IRL for the 2003 Gulf War (but not, in the event used). F.3s were converted to 'EF.3s' by adding two ALARM missiles on GR.1 pylons refitted under the fuselage, and re-activating the outer wing pylons to carry BOZ and PHIMAT pods. Let's therefore say that they decided to continue this role with a more extensively adapted airframe. The radar and the remaining gun are removed and an internal ESM/ECM system fitted, with forward and side-facing aerials under the original radome (or in a new 'tin' nose with multiple dielectric panels) and with rear and side-facing aerials in a fin-top pod. The outer wing pylons could carry BOZ pods or ALARMS, and ALARM has also been carried on GR.4 inboard and Sidewinder pylons. GR.4s could also carry three ALARMs under the fuselage: I don't know why the EF.3 seemed to be restricted to two, but this could be addessed in the upgrade.
2. Reconnaissance.The GR.1A has always been responsible for the low-level recce role and is very good at it, so they were the natural choice to carry the new RAPTOR pod in real life. However, this pod is a LOROP system who's performance is improved by being carried at altitude, and IIRC, there were some mutterings about the GR.1's altitude performance not being good enough to get the best out of it. The F.3 has better high-altitude performance and range, so the RAF takes some of the redundant airframes and converts them to carry RAPTOR instead. The airframe mods don't
need to be anything like as extensive as for SEAD, but since the SEAD aircraft are getting a new EW system anyway, the RAF might plausibly go one step further and fit both EW and RAPTOR to all the retained airframes, thereby giving a homgenous and flexible force. They only had eight RAPTOR pods anyway, so separate recce and SEAD squadrons would be awkward.
I'd see an optimal force of two squadrons of dual-role SEAD/LOROP aircraft ('Tornado EFR.5s?') retained in service, with the rest of the F.3 force RTP'd (cannibalised) to provide a low-cost spares source. They could probably keep such a force going well into the 2020s, i.e. beyond the GR.4 retirement date, which might be particularly relevent since I read that the Typhoon cannot carry RAPTOR since it's physically too big for it...
