New tyres

It may be my computer but you're photo isn't there? Just a grey rectangle. What are the numbers?

When I had mine changed once I just took the caravan to the local tyre place (National tyres I think) and let them do it all. The last time the dealer did it at the service but I think they just got a mobile tyre company in.

185R14C 102/100R

Can you remove the wheels? Even if you can do only one at a time, just take the wheel(s) along to a tyre depot and ask for "one like that, please". They generally don’t appreciate having caravans towed to their workshops but if all else fails…..

Tell them it’s for a caravan and make sure the new ones are of a recent production run. Learn to read the date codes - I can see that yours was manufactured in week 7 of 2017. Finally, ask them to balance the wheels.

https://www.kwik-fit.com/tyres/information/tyre-age

185 in the tyre width in mm while the 14 is the diameter of the rim in inches. I've always thought it funny the two units are in one! There should also be a number between the 185 and the 14 - the height to width ratio or percentage. Many a good maths lessons to be got from those numbers 

As TW said just ask for the same please.

PS when I took mine to the tyre place I did phone ahead and make sure a caravan can be towed in and out without unhitching

If there is no "aspect ratio" along with the width and diameter it is taken as being 80.

You would be looking for something like 185 80 R14c 100/102.

You do not need to spend premium money on a caravan tyre as it is not subjected to the forces that a car copes with. Look at the performance letters for braking and economy that they have to include by law, similar to electrical appliances. 

Colin

A local (to me) tyre place will fit tyres at home for £15 .... I'm sure Karl will have something similar

Your tyres will last longer if you always protect them from the sun and chock them up if not using the van through the winter. You can probably get seven years out of them then, subject to checks of the sidewalls.

Key data for you is;

185 = width

14 = rim diameter

C = commercial ie heavier duty

I have recently bought two similar tyres from Kwik Fit. Trailermaxx eco fitted on my drive by a friendly, helpful guy who said they often fit caravan tyres. They are familiar with Tyron bands, tpms and high pressure valves.

I was very pleased with the service.

Have you tried your local tyre dealer? Just ensure they know that the tyres are for a caravan.  A few phone calls will solve your where to get them from question.