We have traveled extensively having visited 83 foreign countries. Done a lot of travel in the UK, love the countryside.
Also, we did a great tour of Northern Spain and Southern France, visiting your Option 2, except Marseille (we did that on anther trip.
The main difference in COST between the two is the amount of time you plan to stay in London and so a lesser degree Edinburgh.
Large cities in Europe are significantly more expensive than smaller cities or towns in the countryside.
The Basque region of Spain and Bordeaux, along with Carcassonne (DO NOT MISS IT) and Toulouse would be cheaper, but not so much cheaper if you visit the UK countryside. Even great cities like York, Durham, Bath, etc. are cheaper than London.
You can save in London by staying in Premier Inns. There are several spread all over London. The are somewhat comparable to a Holiday Inn Express, but clean and reliable.
You probably need to rent a car to do a nice tour of Option 2. If you do the countryside in the UK, you will need a car as well, but not in London or Edinburgh.
In Bath, consider the Brooks Guesthouse, it is in a great location and wonderful breakfast. The Scallop Shell restaurant is close and has the BEST fish and chips in England.
Also, if you drive in the UK consider visiting the Cotswolds. We stayed at Chipping Campden at the Volunteer Inn.
If you like the out of doors, the Lake District is great.
Also, visit York it. is my favorite city in the UK. Wonderful history at the Minster and some great museums, especially the National Railway Museum. The Minster Hotel is great, with parking and near the north gate of the ancient city.
Suggest stoping to see Hadrian's Wall, it is not so high anymore, but it should be seen. At Haltwhistle, England there is the side of a old Roman fort that is interesting. Durham is another great city to visit.
Also, don't miss Windsor Castle and Stonehenge.
If you go to Spain and France, consider including Arles, Ponte du Gard (ancient Roman aqueduct) and Monaco.
If you like modern art, the museum on Bilbao is special. San Sebastián is great as well. The Bordeaux wine district has many great wineries. Also, as I mentioned, do not miss Carcassonne, it is a walled city of some significance. It is awesome.