Transfers in London

https://www.blackberrycars.com/

I’ll let others answer you question about transport to Southampton.

BTW if you have Google Map you can see how close Victoria Station is the Belgrave House Hotel.

EDIT: then again the above Belgrave might not be your hotel. Do you have an exact address.

Yes, looking on Google maps, Victoria station is close to your hotel, and Pimlico tube station is closer still.

You have two choices- while there are trains from Victoria to Southampton they are local services which take a very long way round. So you are far better off taking a taxi the Waterloo station (a bit further than Victoria but only about 2 miles, rather than Victoria which is about 1/2 mile) and catch a fast train from there. It takes just over 1 1/4 hours and when bookings open 12 weeks from travel date you should get it for £14.50 then taxi to Berth 101- the City Cruise Terminal (there are 4 ships in that day, so you need the right terminal).
The taxi in London will drop you at a level entrance to Waterloo by default, but ask the driver to be sure.
Once in the station all is level access. At Southampton the taxi rank is outside the London bound platform but there are lifts on either side to help you up to the bridge to cross the tracks, then level access to the taxis.

Alternatively you could taxi to Victoria Coach Station and take a National Express coach then cab in Southampton. Either from train or coach stations it is a very short ride which many people walk it's so short.

National Express- https://book.nationalexpress.com/coach/#/choose-journey?journeyType=single&departureStopId=57366&destinationStopId=65136&departureDate=22%2F10%2F2023&departArrive=DepartAfter&outboundTime=00:00&returnDate=22%2F10%2F2023&departArriveReturn=DepartAfter&returnTime=00:00&adults=1&children=0&infants=0&euroAdults=0&euroChildren=0&euroSixtyPlus=0&euroInfants=0&ouiAdults=1&ouiChildren=0&usingCoachCard=false&youngPersonCards=0&seniorCards=0&disabledCards=0&partnerId=NX&campaignId=DEFAULT&request_locale=en&numResults=4

can be booked now. I would suggest the 0830 coach arriving at 1040, but the 0930 arrives at 1205 which is still good time for your ship. Fares start at £8.70. The coach station has level access throughout.

As this is a Sunday check 8 weeks out in case there is engineering work on the train line. They may not offer tickets until the 8 week point if engineering work is expected.

One of your dates is presumably wrong. I assume that you aren’t arriving at the Be
Grave on 22/10 and then leaving on the same day to Southampton.
To get from Heathrow to the hotel it’s very easy to get to Victoria on the tube, with no steps necessary at all. Take the Piccadilly line from LHR and change at either Hammersmith or Baron’s Court to the District line to Victoria. Don’t worry about the change - it is literally 10 feet across the platform from one to the other. It will take around an hour and cost £5.60 each.
You can book a car to take you and Claudia’s suggestion of BlackBerry Cars is good. It will cost a lot more (maybe £80-100) and is unlikely to be any quicker, may well be slower.

Since you mentioned not lugging suitcases on stairs, be aware that Pimlico station is not stop free. You will encounter stairs.

Get off at Victoria and get a cab. Just follow signs to the taxi rank.

Another option from Heathrow is the National Express coach to Victoria Coach station. It's near the Victoria rail station. Then a taxi to your hotel.

No stairs at Heathrow. All escalators or elevators.

But the easiest is a pre-booked car. They meet you as you exit customs, help you with your luggage to the car, and drop you in front of the hotel.

Just to add to the excellent advice you have already received. Besides blackberry cars, there are 2 other airport car services that I have seen recommended. www.justairports.com and www.simplyairports.co.uk.

The person who pointed out the date error is correct. The cruise leaves Southampton Oct. 22. We actually arrive in London at The Belgrave a few days early to see the city. We thank the person who warned us about the labor issues with trains and buses currently. We just experienced that first hand attempting to take the chunnel from Paris to London last May when the train went on strike right there in the station; this is why we are having to return to London so soon thereafter. We are convinced, no more European trains for us. We have made our decisions regarding both transfer issues, and thank all contributors for their very helpful advise. See you at tea!

look up GoOpti and see if they are available. great car service. SAR discounts!!!!

are go opti active in the UK? Certainly not a local company if so. What is a SAR?

Thanks all. SAR comment was from my brother. SAR is old fraternity from our youth many many years ago.