yan, basically your trip looks good, but I might suggest a few tweaks.
Tue: I wouldn't do CoG and HGP. If you don't mind crowds and waiting, do CoG, if you like smaller numbers and minimal waiting, do HGP. They are not the same, but even the much smaller HGP 'ceremony' is interesting to watch.
You could add in here a FREE visit to the Sky Garden in the 'walkie talkie' building. It's free but you must book online in advance. Note: Airport security rules apply, and dress code is smart casual, but well worth a visit for the views. If you book a table at one of the Restaurants, obviously the you pay for what you order. If you visit the Garden for free, you can still use the Sky Pod Bar without a reservation, but may not be given a table, no big deal if just having a coffee.
Wed: ToL at opening time to minimise crowds, walk over Tower Bridge and 0.5m along the South Bank to Borough Market. Getting there around midday for lunch, it will be super busy, it always is. So you basically have the afternoon free here. As per suggestion above, a River Taxi from Bankside (by BM) to Greenwich is a great idea if the weather is nice. If not nice, maybe drop the London Transport Museum in here, as Covent Garden isn't too far away from BM, walkable for sure.
You could add Vinopolis if doing the BTM, if the world of wine interests you.
Also, you're basically at Shakespeare's Globe here, so could take 30mins for a look.
Thu: Oxford/Bicester makes much more sense than Cambridge/Bicester. Bicester is just shopping, high priced clothes at reduced prices, but still not cheap imo.
Maybe forget Oxford/Bicester and do Windsor Castle instead, closer, cheaper to get too and ultimately more fun I'd say.
Fri: looks good, if moving either Greenwich or BTM to Weds.
Sat: looks good, TS, PC and LS are basically walk throughs taking 30min at most.
Sun: looks good.
All in all, one of the most sensibly planned trips I've seen on here.
Personally, I'd do the Tower Bridge glass floor and not go inside the Royal Observatory, you can still see the Meridian Line from outside, and there is a path in front where you can take pictures straddling the ML. The River Taxi will take a touch longer (30mins trip time by boat) than the DLR but all said and done, you talking a few minutes in it, and the RT is much more fun, and good value if you get a return ticket.