SP46
"Britain's best-selling self-propelled petrol"
RRP New
£329
Manufacturer
Buy Now
£279
Lowest UK retailer
Used Avg
£140
Facebook / eBay UK avg
★ 4.3 (1,240) · Value 8.6/10
Full SP46 review →
MX46SPB
"Briggs-powered budget self-propelled with rear roller"
RRP New
£399
Manufacturer
Buy Now
£399
Lowest UK retailer
Used Avg
£200
Facebook / eBay UK avg
★ 4.4 (845) · Value 8.2/10
Full MX46SPB review →
Verdict — which one to buy
Our take
Same cut width, same price band, similar build. Mountfield wins on parts availability and dealer network; Cobra wins on the rear roller (stripes) at this price. If stripes matter, take the Cobra; if not, the Mountfield is the safer used buy.
Spec-by-spec
| Mountfield SP46 | Cobra MX46SPB | |
|---|---|---|
| RRP | £329 | £399 |
| Buy now | £279 | £399 |
| Used avg | £140 | £200 |
| Type | Petrol | Petrol |
| Engine / Power | Stiga ST120 OHV 123cc | B&S 500E Series 140cc |
| Cut width | 46 cm | 46 cm |
| Weight | 27 kg | 30 kg |
| Self-propelled | Yes | Yes |
| Rear roller (stripes) | No | Yes |
| Mulching | Yes | Yes |
| Bag capacity | 55 L | 60 L |
| Suited to lawn | Medium | Medium |
| Noise | 95 dB | 95 dB |
| Rating | 4.3 / 5 | 4.4 / 5 |
| Value score | 8.6 / 10 | 8.2 / 10 |
Pros & cons of each
Pros
- Best-value self-propelled petrol on the UK market
- Stiga engine is reliable and parts are everywhere
- Light at 27kg — easy to push and store
- Huge used supply keeps prices low
Cons
- Plastic deck not as durable as steel
- Cable-operated drive less smooth than Honda
- Rear flap hinge a known weak point
Pros
- Rear roller for stripes at budget price
- Briggs & Stratton engine — well known
- 60L grass box is generous
- Self-propelled with key start option
Cons
- Cobra dealer network is thin
- Plastic wheels and deck feel cheaper
- Roller bearings degrade quicker than premium brands
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