I done it for 500L MPW, not 500L.
500L MPW has longer exhaust pipe and rare to get, however front flexi bit is the same.
You can buy ready product, flexi pipe with a bit of exhaust pipe and a clamps, however, I like to self educate, I like save money here and spend there, so I done just flexi pipe replacement and this guide is not only to show you "how to", but as well to point you that if you're afraid of welding then it's really worth to try and expand your own education:

- Flexi pipe: 200mm long, pipe size: 50mm. I've used dedicated one for Panda as only for Panda I was able to source: 200mm long, 45mm pipe size + 20cm long pipe of 52mm size.

- Welder: just gasless wire one, about £100 - £150 : 40-50A however I bought Einhell with 45A/90A switch. (£130). While doing research some (idiots) kept talking about 90A because is better - none sense because while using I found that 90A is too strong for mild steel which is exhaust it means I was doing holes in it. So, more "A" doesn't mean better for beginner at all. No one mentioned to me to get one dual with switch, so bear in mind this option is helpful. I seen negatives regarding gasless and positives regarding gas one, but still I went for gasless, wire one and it was the best decision. I'm beginner so gasless is a bit more challenging to make beautiful joints however this is under car and one tiny bottle of gas thats about £20 while 108m of Lidl reel wire only £3.99 (I've used half reel) so make your figures in here + gasless one is so small unit. Welding face mask: ignore stock ones, buy Lidl one, good stuff, does works on batteries so I could see all the time what I was doing without any harmful stuff for my eyes.

Tools:
- hammer, flat screwdriver, spanners, WD40, caramic grease, angle grinder and obviously welder.

1. remove clamp bolt right under engine which joints exhaust with DPF. 17MM socket. Clamp is not removable, just untight it.
2. Remove two rubber supports just behind flexi pipe. Do not remove from exhaust, too hard, just slide out from the car mounted bracket, a lot easier.
3. use flat screw driver and hammer and slide out exhaust, this is the hardest bit. It goes so slow. If not corroded much then you will find on top of it little metal pin so you can put screwdriver against it. Use WD40.
4. Cut pipe just after flexi pipe.
5. When whole element out then cut off flexi pipe completely so you have now raw exhaust pipe without flexi bit.
6. I couldn't source Flexi pipe for 500L 50mm so I bought for Panda 45mm + 20cm 52mm pipe:
- cut 2cm of 52mm pipe and attach to your exhaust pipe, 1cm in, which you removed from the car and weld it around. It's great opportunity to learn and train your welding skills as you're working out of the car.
- Now you can fit flexi pipe to your welded extension - and weld it together.
- Now cut another 2cm of your 52mm spare pipe and weld it to other side of flexi pipe.

NOW IMPORTANT BIT: DO NOT WELD THIS COMPLETELY BIT TO YOUR EXHAUST PIPE UNDER CAR! NOT YET!

7. Grab your complete welded flexi pipe, go under car and join it to DPF pipe, you will see on DPF pipe little metal pin which must lock in to your pipe, this is indication how far it must be fitted and which way.
8. Now push exhaust pipe towards back and check how much pipe you must cut off to be able joint that 1cm of previously done extension. I had to cut only 2cm. Be careful there and think, if you cut too much then you need to use your 52mm spare pipe to fill the gap.
9. Use ceramic grease on to DPF pipe.
10. When done, now attach your hanging exhaust in to flexi pipe, push it all towards back, bend flexi pipe and attach to DPF pipe and slide it in until you reach locking point.
11. If you're unable to do it then remove and cut off about 0.5cm or how much you need, just be carefull.
12. When all done, fitted and matched, THEN WELD while fitted, just bottom side, so this way you're sure that is correct angle etc. DISCONNECT BATTERY FOR WELDING ON THE CAR!
13. Slide out whole exhaust again so while hanging you get more space and better access to the top of it, weld weld weld...

Job done.

As you can see my welding is really very bad, but I don't care, I'm learning it, it was my second time welding in my whole life, most important thing is: it does work and it's 100% seal.

Why ceramic grease? I used it a year ago on same pipe while doing timing chain, I found this time it was far easier to remove exhaust + this ceramic grease is helpful when you have to fit/remove pipe several times.