Our verdict
The default "I just need a petrol mower from B&Q" buy. Performs above its price thanks to the Briggs engine, but build quality is honestly below Mountfield. Decent value new, fair used.
Pros & cons
Pros
- B&S engine — well known and serviceable
- Self-propelled at budget price
- 46cm cut suits average UK lawn
- B&Q dealer support across the UK
Cons
- Plastic everything — flimsier than Mountfield
- 3-year B&Q warranty is generous but limited to original buyer
- Resale is poor
Full specs
| Type | Petrol |
|---|---|
| Cut width | 46 cm |
| Engine / Power | B&S 500E Series 140cc |
| Weight | 29 kg |
| Deck | Steel |
| Self-propelled | Yes |
| Rear roller | No |
| Mulching | Yes |
| Cutting heights | 6 positions |
| Bag capacity | 55 L |
| Suited to lawn | Medium |
| Noise level | 95 dB |
Buying second-hand
£70–160 used. Briggs engine is the only durable bit — if it runs cleanly cold, the rest can be fixed. Drive cable and plastic chassis cracks are the common faults. Never pay more than £150 — there is always another at B&Q for £270 new with warranty.
Where to buy the Mac Allister MPRM46SP
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Repair-cost reference
UK 2026 ballpark prices for the parts you're most likely to need on this mower. OEM is dealer-genuine; aftermarket is what you'll find on eBay or generic small-engine suppliers. Use these to sense-check any quote and to negotiate on used buys.
| Part / job | OEM | Aftermarket |
|---|---|---|
|
Replacement 46cm blade
Annual sharpening is free; replace when bent or cracked.
|
£24–£32 | £8–£12 |
|
Air filter (foam)
|
£12 | £4 |
|
Spark plug (NGK BPR4ES)
|
£8 | £3 |
|
Primer bulb
|
£6 | £3 |
|
Drive cable replacement
Stretches at 5–8 years. 30-minute DIY fit.
|
£18–£28 | £8 |
Fair-offer calculator
Tell us about a specific used listing for the Mac Allister MPRM46SP you're looking at. We'll compute a fair offer range from our used-market data and the condition signals you provide.
Calculations are guidance, not gospel. Used-market prices vary by region (Scotland is typically 10–15% cheaper than the South-East), season (October cheapest, March most expensive), and seller motivation.
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