Hi all , I have a 2018 Octavia and looking to purchase a Dpf sensor , my car has engine code DGTE but upon searching for the part it keeps.coming back with DDYA but says it will fit my car , is this correct , thanks in advance for any help ? 

Can you not read the part number off the existing sensor?

 

Not without a ramp no 

I know it’s eBay and prob not the most reliable hence me asking her 

Ah, sorry, for some unknown reason I thought you meant DPF pressure sensor, which is generally viewable under the bonnet from above. 

Is it a temperature sensor you need instead? If so, which one, there's usually a few?

Not sure, wasn’t aware there was more than one , had my engine light on a couple of times recently and had a diagnostic check done again today , codes have been cleared but was told again it’s temp sensor that’s coming up as an issue 

It's a bit of a minefield trying to work out what's what.  Have a look at this page, on a computer rather than phone, and see how many different sensors are shown in the exhaust system:

LLLParts

 

If the one you need happens to be the first temperature sensor nearest the engine, first item 3 then it looks to be the same for both of the engine codes you mention, plus one or two others.

The comment above that is telling though - 

Before parts order,
physical inspection of
old part necessary

Before parts order, physical inspection of old part necessary

 

FairPlay to RRG i picked my car up today , they’d run a diagnostic check and done a regen neither of which are covered under warranty free of charge.

cleared codes so gotta wait for light to come back on to pin point issue. 
They also couldn’t find my key ,someone else’s key was on my hook but they’d been and gone, fair play to them the guy on the desk gave me his car keys to use to get home , few hours later they turned up with my car , keys and a bottle of champagne