I've done too much research - my head is spinning! Can you please guide me to get what we need? I know this has been done to death but I am finding it confusing.

We have been to London before and already have Oyster cards which we used exclusively last time as I didn't know about the other options. We are staying at the Morgan Hotel in Bloomsbury for 7 nights and will be using the Tube to travel to and from Heathrow.
Our itinerary is pretty laid back as we have seen most of the biggies, so mainly just wandering around, museums, parks, gardens, theatre and using the Tube or bus to get around when we get tired.
We intend on taking the Eurostar for a day trip to Paris. At this stage we will only be using one 2 for 1 to visit the Tower of London.

Do we just stick with our PAYG Oyster and buy a National Rail ticket from Charing Cross to Waterloo East and return (as was suggested on an earlier thread) for our Tower day? Is a Travelcard of any benefit to us?

Thank you!

You can use your PAYG Oyster on the National Rail to Waterloo East. The turnstiles will have a place for you to tap in an out, just like the entrances to the tube. Don't bother getting a National Rail ticket.

I don't want to go to Waterloo East, its an option to be able to use the 2 for 1 vouchers so we can get a National Rail ticket.

Can't see why you should pay more than you need to - if you are having to go to a train station anyway to get a ticket you may as well just buy a one day Travelcard and use it on that day for both travel and the 2-4-1 offers - saves you the cost of the train ticket and it won't cost you any more than the Oystercard PAYG that day.

If you aren't in walking distance of the station then buy the Travelcard the day before ensuring it's dated for the right date

Fantastic,that's great! So the Travelcard takes the place of the Oyster for the day we want to use the 2 for 1, so simple.

Thanks heaps for clearing this up alanRowe. I feel so much happier now.

Just to confirm -- yes that is definitely the way to go. A slight diversion into a train station to buy the one-day travelcard - but it will save you £17 and extend your PAYG Oyster balance since you won't use it that day.

Excellent news, janisj. I just read so much I kind of got lost in it all and was over thinking it.

Thank for clearing it up.