Expect an older appliance. Most DeLonghi ovens in Sydney date from the 2000s or 2010s, so the cavity carries baked carbon rather than grease and needs repeated applications with dwell time rather than harder scrubbing. Some models carry catalytic liners that must be left alone.
DeLonghi is better known in Australia for coffee machines, but through the 2000s and 2010s it sold a great many built-in and freestanding ovens into Sydney apartments and townhouses. Almost every one we open now is well into its second decade.
That age is the defining fact, and it changes what a realistic result looks like.
Carbon, not grease
An oven that has been cooking for fifteen or twenty years does not carry grease. It carries carbon: fat that has been heated, cooled and reheated several thousand times until it behaves more like varnish than like anything you could wipe.
The practical difference is that mechanical force does almost nothing to it and contact time does almost everything. A single application of cleaner wiped off after five minutes will lift the top layer and leave the rest, which is why so many DeLonghi owners conclude the oven is beyond saving after one attempt. Two or three applications with a full thirty minute dwell each will take off what an hour of scrubbing will not, and our oven cleaning guide covers the method in detail.
The temptation at this age is to escalate to something abrasive. That permanently dulls the enamel, which then holds dirt worse than it did before, so the second clean is harder than the first.
Check for catalytic panels first
Some DeLonghi models carry catalytic liners on the rear wall: rough, matte, slightly porous panels. On a twenty year old oven they look exactly like an area that has been neglected since installation, which is precisely why they get attacked.
They are the cleaning system, not dirt, and scrubbing or spraying them destroys the coating permanently. If a rear panel is rough where the side walls are smooth and glossy, leave it alone entirely and clean only the enamel around it.
Freestanding or built-in changes the job
DeLonghi sold both, and the distinction matters for what you are actually cleaning. A freestanding DeLonghi is one appliance with its cooktop, so the hob, the oven and the grill compartment are a single job and it is priced as a stove rather than as an oven. A built-in is just the cavity, with the DeLonghi cooktop above it as a separate surface.
The second owner problem
An apartment built in 2008 with a DeLonghi kitchen has typically changed hands two or three times since. Each buyer walked through, saw a kitchen that looked acceptable, and reasonably assumed the previous owner had maintained it.
Nobody had. Ovens do not fail visibly, they simply get worse in a way that is invisible over months and obvious over a decade, and there is no point in that chain where anyone was prompted to act. So the appliance arrives at us carrying the whole history rather than one owner's share of it.
This is worth knowing for two reasons. It sets expectations, because the first proper clean on an oven like this takes considerably longer than the ones afterwards, and it should be quoted that way rather than as a surprise. And it means the finding is frequently not the oven at all: the seal has gone, the hinge springs have weakened so the door no longer closes flush, or the rangehood above has never been opened and has been putting grease back on the oven front for fifteen years.
If you have just bought an apartment with a DeLonghi kitchen, treat all three appliances as untouched rather than as maintained. That is not pessimism, it is what the pattern of ownership makes overwhelmingly likely.
What actually goes wrong
One application and a conclusion, on a cavity that needed three.
A scrubbed catalytic panel, believed to be twenty years of neglect.
A perished door seal, near-universal at this age, cheap to replace, and frequently the actual reason the oven browns unevenly.
A smell after a spotless clean, which on fan models is the chamber behind the rear baffle.
Should you do it yourself?
Do it yourself if you are prepared to apply cleaner three times over an afternoon rather than once. That is genuinely the whole technique on an appliance this old.
Get someone in if the cavity roof has gone hard and black, if you are unsure whether a rear panel is catalytic, or if the DeLonghi is freestanding and the hob has set solid as well.