Just don't worry about HDR right now with monitors unless you are spending thousands. People don't realise that most LCDs that are marketed as HDR displays are actually gonna look mostly to 100% worse in HDR than SDR, eg any LG LCD, any Sony LCD below the 9-series, and Samsungs LCDs ("QLEDs", they are LCDs though, most mid-range and above LCD TVs are "QLEDs", ie contain a QDEF layer in the LCD stack) below the Q80A (or in future years whichever QLED is the first FALD one) because LG use only IPS panels, and anything that isn't VA and/or FALD will have really obvious blooming/black levels compared to SDR (unless your backlight is at max in SDR anyway, which is shouldn't be).
Only VA FALD (SUPER high zone count IPS FALD is acceptable but the contrast ratio is still trash) and OLED produces even good HDR, let alone great HDR or awesome. Great is relegated to around 10 models across the brands in any given year and awesome HDR is only on OLEDs and very specific VA FALD LCDs, most of which aren't old models and not available new, so basically you need an OLED.
I say save up and buy a QD-OLED monitor or wait for them to be more affordable, the LCD monitors with great HDR are stupid money, don't buy them, you would just buy an 42"/48" OLED in that case. I'd be waiting, I don;don't think its a good idea to buy first gen products, like the current QD-OLED monitor(s).
Yeah you can get the 48A1 for stupid low money right now, but people will probably say thats not a good gaming display as its limited to 60hz. Unless you mean a 48C1 for £499? That would be amazing but afaik its £800 even in Costco, its £869 at most regular retailers as of Monday, but its a forward order in many places.
TL;DR - Just wait for better prices on QD-OLED monitors or buy an LG 48C1. It can't be done for 5 hundo though.